Download Solar passive design – combining orientation, thermal mass and

Factsheet 1. Solar passive design – combining orientation, thermal mass and windows
Factsheet 2. Insulation – retaining the heat in your home, not heating the neighbourhood
Factsheet 3. Sealing – eliminating draughts is crucial to a comfortable and efficient home
Factsheet 4. Heating – the most important home appliance purchase you will make
Factsheet 5. Hot water heating – the second-largest energy user in cold climates
Factsheet 6. Balancing the double-edged sword of windows
Factsheet 7. Understanding Energy – basics for Homeowners
Factsheet 8. Site Selection
Factsheet 9. Energy Efficiency
Factsheet 10. Green Healthy Materials
Factsheet 11. Lighting
Factsheet 12. Ventilation and Cooling
Factsheet 13. Waste Management
1. Solar passive design – combining orientation, thermal mass and
windows
There is one form of energy that is easy to access with clever building design, and completely free –
the Sun! Correct application of the principles of solar passive design allows any building to trap the
heat contained in sunlight as free heating in winter, while minimising entry of sunlight to the building
in summer to prevent overheating. This can lead to greater comfort, low or no heating and cooling
costs, and a significantly smaller environmental footprint for passive solar buildings.
Sun angles in Googong
Earth’s vertical axis, the line around which the planet spins, is tilted 23.5° from vertical. As Earth
orbits the Sun, this tilt means that the angle of incoming sunlight changes relative to the ground.
This effect causes the seasons and also influences the way buildings are affected by the heat in
sunlight.
In Googong, at latitude 35.4°, on the summer solstice (December 22) at midday the Sun is 78.1° from
horizontal, almost directly overhead. On the winter
solstice (June 22) at midday, the Sun is 31.1° from
horizontal, low in the northern sky. The Sun moves
between these extremes at roughly 8° per month.
Properly accounting for this change of Sun angle
when orienting and designing a house can
significantly reduce the need for heating and
cooling. This in turn improves comfort, reduces
energy consumption, energy bills and greenhouse
gas emissions. Here is a useful application for you to
visualise where the Sun is at any time of year (set to
Googong, although you can change it to anywhere on the planet):
Figure 1 – the impact of sun angles
http://www.suncalc.net/#/-35.3916,149.2348,12
Sun angles and building orientation
You do not need to know exactly where the Sun will be on every day of the year to understand how
to orient your home – it is simply a matter of orienting to maximise incoming sunlight in winter and
minimise incoming sunlight in summer. Put simply, to take advantage of solar passive design, your
home should be oriented with the long axis as close to true east-west as possible. This maximises
exposure of the building's surface area to the north, maximising the sunlight entering the building’s
windows in winter, helping to warm it during the day. This orientation also minimises exposure of
the building to the east and west, which minimises sunlight striking the building in summer, keeping
it cooler during the day in summer. The correct orientation helps in both seasons!
Figure 2 – correct orientation maximises exposure to sunlight in winter, minimises exposure to sunlight in summer
Thermal mass – storing the heat in sunlight
Thermal mass is the ability of a material to absorb and retain heat. All materials have some degree
of thermal mass, but many cannot store large quantities of heat (e.g. wood, plasterboard), while
others re-radiate heat rapidly rather than retaining it (e.g. metals). Water has the highest thermal
mass of any common material on Earth, but we cannot build with water, so the best thermal mass
for building includes heavy materials such as concrete, brick and stone.
Thermal mass materials absorb heat from the air when they are cooler than the air around them,
and release heat to the air when they are warmer than the air around them. They also absorb heat
from radiant heat sources like sunlight or heaters.
The best way to use high thermal mass materials in building is to place them inside the building
where they will be hit by sunlight during the day in winter – in front of north-facing windows is ideal
– but are shaded from sunlight in summer. Used in this way, the high thermal mass will absorb the
heat from the sunlight which strikes it during the day, warming the thermal mass. Then, when the
air cools below the temperature of the thermal mass at night, it will start to release the heat
absorbed during the day. This heat absorbing and releasing property of high thermal mass materials
acts to reduce temperature fluctuations within the house, making it more comfortable.
Windows – letting the sunlight in!
Solar passive design requires sunlight to enter a building in order to be useful. This is called solar
access. Sunlight that hits external walls is of little benefit, even if it strikes a thermal mass material
like brick, because that brick is outside the building envelope and has insulation between it and the
living area you are trying to keep warm. So, careful positioning of appropriate windows to allow
winter sunlight access to internal thermal mass is extremely important.
Most heating is used in common living areas, so if possible they should face north and feature large,
north-facing windows (see Design). Double (or triple) glazing will not significantly reduce the
amount of sunlight penetrating a window – after all, double glazing is simply two panes of glass with
a gap in-between. However, double glazing will help to keep in the heat by reducing conductive
heat loss, so it is preferable to single glazing. Regardless of glazing type, insulating internal window
coverings, such as pelmeted multilayered curtains or honeycomb blinds sealed to the architraves,
are necessary in a cold climate like Googong to help keep the warmth in at night.
In summer, it is preferable to eliminate solar access through windows because the heat in sunlight
becomes trapped in the house, especially if it is well sealed and insulated. Eaves and other kinds of
structural overhang are designed to block out sunlight when the Sun is at a high angle in the sky in
summer, but any east/west/north windows exposed in summer may require further shading using
external coverings such as awnings or roller shutters (see Shading). Clever design to prevent
sunlight from entering your home in summer will keep it much cooler.
For more detailed information: http://www.yourhome.gov.au/passive-design/.
2. Insulation – retaining the heat in your home, not heating the
neighbourhood
Googong has long, cold winters, so it is essential to have some form of heating. Whether heating is
supplied by the Sun or an energy source like gas or electricity, it is crucial to keep this heat in your
home. The longer the heat remains the less work the heater has to do, the less energy it uses, the
more comfortable you are, and the lower your bills and environmental impact. Heating and cooling
makes up 60% or more of the energy consumption of most households in the Capital Region, so
major savings can be made by reducing the need for heating and cooling. Insulation helps reduce use
of heating and cooling by retaining heat in your home in winter and keeping it outside in summer.
What does insulation do?
Unlike thermal mass materials which store heat, insulation slows down the movement of heat
through the insulation. There are three different ways heat is transferred in and out of buildings:
 conduction: heat that moves through ceilings, walls, windows, doors and floors,
 radiation: electromagnetic waves like the heat in sunlight, and,
 convection: air that moves in and out through gaps in the building (see Sealing).
Different kinds of insulation slow down the movement of different types of heat, and the more
complete the insulation coverage the better it is at slowing down heat movement and keeping your
home at a comfortable temperature all year around.
Different kinds of insulation and how they work
There are two distinctly different kinds of insulation which do very different jobs: bulk insulation and
reflective insulation. It is important to understand the different ways they work.
Bulk insulation comes in the form of batts or loose-fill and is made from bulky materials like
fibreglass, rockwool, cellulose, polyester, or sheep’s wool. The tiny pockets of air trapped within
these materials make them resistant to the conduction of heat – that is, the heat that moves
through things when there is a difference in temperature on either side of them, in this case through
the ceiling, walls and floor of your home. The temperature difference between inside and outside at
Googong on a winter's night can be 20°C or more, so it is an excellent idea to have high levels of bulk
insulation in your Googong home.
Picture 1 – bulk insulation batts (left) and a roll of reflective insulation (right)
Thicker insulation means more air pockets and greater effectiveness at slowing the conduction of
heat in either direction, so bulk insulation will help you in both seasons, more so the greater the
temperature difference between inside and outside. This principle of trapping small air pockets to
reduce conduction of heat applies in all contexts: it is the same way insulating window coverings and
double glazing work, and even the way clothing works to keep you warm.
Reflective insulation (aka sarking, sisilation, anti-con) comes in rolls or boards and looks like
aluminium foil. It acts as a mirror to radiant heat – that is, heat in the form of electromagnetic
waves, such as the heat in sunlight or the heat emitted from bricks, tiles, concrete or metal that is
exposed to sunlight for long periods. Reflective insulation is best at reflecting radiant heat away
from the building interior in summer, but will not help much in winter because most winter heat loss
in cold climates occurs as either conduction (which is what bulk insulation is designed to reduce) or
convection (air moving through gaps in the building envelope).
How much insulation do I need in Googong?
It is standard practice to install both bulk and reflective insulation in modern housing, but from a
home-owner’s perspective it is also a good idea to know exactly how much and what kind of
insulation are being put into your home, and where.
The effectiveness of bulk insulation is measured in R-values. R stands for 'resistance to heat flow',
and a very rough rule of thumb is that 5 cm thickness of standard bulk insulation materials
corresponds to R1 insulation value, although this varies depending upon the insulation material
used. A high level of bulk insulation is an excellent idea in a cold climate like Googong: install R5
bulk insulation above the ceiling, and at least R2 bulk insulation in the walls (and under the floor if it
is suspended – if not, the slab edge should be insulated at the very least, and preferably there should
be insulation underneath the slab as well). Reflective insulation should also be installed under the
roof and in the walls.
Installing high levels of bulk insulation in the ceiling and walls, and wrapping the house in reflective
insulation, translates to greater comfort year-around, and less need for heating and cooling than an
under-insulated or uninsulated building. This in turn will improve the comfort of the house and save
you lots of energy and money over time from avoided heating and cooling.
Full coverage is crucial!
Even small gaps in insulation reduce its effectiveness greatly. For example, a 200m² R5 insulated
ceiling with 10m² of gaps in the insulation would reduce the total ceiling insulation value to about
R2.3, and even 5 m² of gaps in insulation would reduce it to just over R3.1, which means higher
energy consumption and bills for heating and cooling. So, try to minimise the number of holes in
your ceiling insulation by avoiding downlights, installing heating/cooling that isn't ducted through
the ceiling, and otherwise minimising penetrations through the ceiling (see Sealing). Also,
remember to stick a batt on your manhole cover.
For more detailed information: http://www.yourhome.gov.au/passive-design/insulation and
http://www.yourhome.gov.au/passive-design/insulation-installation.
3. Sealing – eliminating draughts is crucial to a comfortable and efficient
home
Googong has long, cold winters, so a high level of insulation is essential to keep your home
comfortable and energy efficient. However, insulation alone is not enough to retain the heat –
draught sealing is also absolutely essential to keep the warm air in! There is no monitored regulatory
standard for air leakage from Australian houses, but that does not mean that draught sealing is not
important. To the contrary, paying attention to draught sealing during construction is very
important as it is much easier and cheaper to get it right from the start than having to rectify it later,
and a high level of draught sealing will potentially save you a lot of energy and money over time.
Measuring air leaks in housing
The most common measure of air leakage from housing is Air Changes per Hour at 50 Pascals, aka
ACH50. This is determined using a blower door – an apparatus incorporating a powerful fan that fits
on an external door – to create a 50 Pa pressure difference between inside and outside the house.
The rate at which the house loses pressure is then measured. A decent ACH50 is 7, the lower the
number the better. The most stringent energy efficiency regulation in the world, German
Passivehaus, requires an ACH50 of 0.6, while Australian housing often has an ACH50 of 15 or higher.
There are local companies that leakage test houses, pinpoint the location of leaks, and make
recommendations about how to address them. However, it is cheaper and more effective to make
sure your house is properly draught sealed during construction, so it is a good idea to speak to your
builder about their use of draught sealing techniques and devices.
Where are the common air leaks in housing?
There are many potential sources of air
leakage in new houses including:
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downlights or recessed lights
door and window framing (gap
between window/door frame
and wall frame)
floor to wall and wall to ceiling
joints (can be hidden behind
skirting/cornices respectively)
internal wall cavity sliding doors
(cavity in wall not sealed
properly) and built-in wardrobes
evaporative cooling vents
wall-mounted reverse cycle air-conditioners (RCACs)
gas or wood fireplaces or heaters with chimneys
Figure
or1flues
– possible air leaks from housing
plumbing and gas penetrations, phone and television cable penetrations
doors (gap between door and floor, gap between door and doorframe)
dog/cat doors
exhaust fans (if not fitted with a draught sealing device, including clothes dryer vents)
electrical sockets
Gaps and cracks can develop over time as a building settles, and seals on doors (especially sliding
doors) and windows can wear out, so it is a good idea to address air leakage every few years as an
ongoing maintenance issue (see DIY sealing videos here: http://www.greenityourself.com.au/ ).
How can air leakage be addressed during construction?
Each source of leaks requires a different solution, but most are easy enough to apply during
construction if sufficient care is taken:
Downlights or recessed lights: avoid installation (cheapest/easiest solution); or, install high
temperature-resistant LED downlights1 with sealed fittings, and fire retardant, insulating downlight
covers2 in the ceiling above the fittings – this allows insulation to be installed up to the cover.
Door and window framing: appropriate sealing tape, caulking or foam sealant during construction.
Floor to wall and wall to ceiling joints: appropriate sealing tape, caulking or foam sealant during
construction.
Internal wall cavity sliding doors and built-in wardrobes: the cavity into which a sliding door slides
should be enclosed in all directions, as should the space above and below built-in wardrobes.
Evaporative cooling vents: during winter, attach removable Heat Saver3 covers, an Australian
invention. Remove during summer to allow for evaporative cooler operation.
Wall-mounted RCACs: appropriate sealing tape, caulking or foam sealant during construction.
Gas/wood fireplaces/heaters with chimneys/flues: can be tricky and must be treated carefully –
discuss with your builder and/or heating specialist.
Plumbing and gas penetrations, phone and television cable penetrations: appropriate sealing tape,
caulking or foam sealant during construction.
Doors: many doors now come installed with seals, but if not, add a bottom door draught stopper
and appropriately thick draught sealing tape around the doorframe, both available at any hardware
store. Also, draught seal the door to the garage (often forgotten), and doors such as the laundry
door, which can potentially create an ‘airlock’ in conjunction with the back door.
Dog or cat doors: install airlock pet doors. Minimise the number installed.
Exhaust fans and Tastics: only install automatically self-sealing exhaust fans and Tastics.
Electrical sockets: install airtight electrical sockets and socket plug covers for sockets not in use.
All of these products can be sourced with minimal internet searching, and the extra upfront cost of
properly draught sealing your home will pay itself off rapidly.
Ventilation and moisture
A well sealed house will require some level of ventilation, depending on exactly how well it is sealed.
For example, houses meeting or close to the Passivhaus standard require heat recovery ventilators
(HRVs) for constant ventilation, while a well sealed Australian house could probably get by with
active ventilation by the occupants (ie. opening doors and windows as required).
To avoid problems associated with moisture buildup, wet areas (kitchen, bathroom/s, possibly
laundry) should have externally vented, self-sealing exhaust fans which are used whenever a
moisture-creating activity, like showering, cooking, or drying clothes, is performed.
For more detailed information: http://www.yourhome.gov.au/passive-design/sealing-your-home.
1
LEDs degrade more quickly under elevated temperatures. See detail here: http://efficiencymatrix.com.au/downlightcover-compatible-led-products/
2
Such as these: http://www.downlightcover.com/index.html or these: http://efficiencymatrix.com.au/.
3
See here: http://www.heatsaver.com.au/
4. Heating – the most important home appliance purchase you will make
More than half of all the energy consumed in your Googong home will likely go to heating, so the
kind of heating you install is a very important decision. Upfront cost is an important factor when
buying a heater, but so is the efficiency of the heater because this influences the size of ongoing
heating costs. Locking in a low efficiency heating option can cost you thousands of dollars more than
an efficient heater over the life of the equipment. So, it is important to choose your heater carefully,
and investing more upfront can save you a lot of energy and money over time.
It is an assumption today that central heating should be installed in every house, but this is a very
modern idea as central heating was not so common even 20 years ago. Rather than assuming you
need central heating, which can be far more costly to run than room heating, carefully consider your
heating requirements. There are two main questions you should ponder before buying a heater:
1. Should I invest in central heating or room heating?
What are your patterns of space usage within the home? For example, do you spend most of your
time in the living room-kitchen area, or will you use most of the house most of the time you are
home? Where are you most likely to spend time during the day/at night? These questions are
important because they will help you to determine whether you need central heating or not.
2. Do I prefer or require a certain kind of heating?
Convective heaters send out warm air to fill a room e.g. gas ducted and gas wall-mounted heaters,
reverse cycle air-conditioners (RCACs). Convective heating can be an issue for people with asthma
or chronic allergies as air movement can stir up allergens. Radiative heaters send out radiant heat to
heat objects directly, and more slowly heats the air in a room e.g. hydronic radiators, bar radiators.
Efficiency in electrical heaters and gas heaters
There are two distinct kinds of electrical heating: electric resistance heating, and RCACs (aka heat
pumps). Electric resistance heating, including column, panel, radiator and fan heaters, provides
about one unit of heat output for each unit of electricity input – in energy terms, think of them as
“one in, one out”. On the other hand, RCACs use electricity to draw heat from outside air, so typical
new RCACs can produce up to four units of heat output for each unit of electricity input, depending
on the outside air temperature. So, RCACs are far more efficient than electric resistance heaters per
unit of electricity consumed, and electric resistance heaters should be avoided if possible.
The efficiency of gas heating depends on the thermal efficiency of the machine – that is, how good
the heater is at separating heat from the noxious gases exhausted
through the flue. Thermal efficiency for typical gas heaters varies
from 60-85%, so 60-85% of the heat produced by burning the gas is
sent to heat the home, while the rest of the heat is lost with the
exhaust gases.
Whatever kind of heating you buy, always buy the most efficient
model you can afford, even if the upfront price is a little higher –
extra efficiency is likely to pay off the added upfront cost rapidly. To
determine the efficiency of a heater look at the Energy Star label
and/or discuss with a heating specialist.
Types of central heating
Central heaters are powerful devices capable of heating your entire house. As such, central heaters
also use a lot of energy, which means they can be costly to run and potentially have a large
environmental footprint. If installing central heating, it is essential to install zoning, which should
help to limit your heating to the areas of the house that are in use. The flexibility of zoning depends
on the type and brand of heater, so shop around if you require highly flexible zoning.
Hydronic heating: hot water pumped through in-slab pipes (make sure to insulate the slab!),
radiators, or a combination of both in two storey houses. The water is typically heated by a gas
furnace or heat pump, and although rare, solar is also possible. Hydronic heating is the most
efficient form of central heating, is zonable to each room in the house individually, produces radiant
heat and also warms the air in a room. It is generally more expensive upfront than ducted heating.
Ducted heating: warm air pumped throughout the house through insulated ducting. The air is
produced by a gas furnace or heat pump. Ducted heating is zonable, but generally to areas and not
to every room individually, produces convective heat rapidly, and should be installed under the floor
if possible (installing it in the roof punches holes in your ceiling insulation!). Avoid putting vents in
rooms that do not need or are not suitable for convective heating, such as bathrooms/laundry.
In-slab electrical heating: electric resistance wires running through a slab. It is very inflexible and
expensive to run. In-slab hydronic is a far more flexible and efficient choice.
Heat recovery ventilation (HRV): used in conjunction with passive solar design, highly efficient.
Types of dedicated room heating
Room heaters are usually dedicated to a particular room (sometimes two rooms). They are less
powerful than central heaters because they are designed to heat smaller spaces, and are
consequently less costly to run. If you typically use only certain parts of the house, such as the living
area and master bedroom, it makes sense to install room heating instead of central heating.
RCACs: a compressor outside linked to a wall unit in one or a number of rooms, pumps out warm air.
New models can be highly efficient and effective at low temperatures, but be sure to check with the
manufacturer for an appropriate model. RCACs can also be used for cooling in summer.
Flued gas space heaters: mounted into a wall, or portable with exhaust duct through a wall/window,
pumps out warm air. Can heat a room rapidly and some models are relatively efficient. Unflued gas
heaters should be avoided as they are potentially dangerous.
Portable electric space heaters: come in many forms – column, panel, bar radiator or fan heater.
They are cheap to buy but relatively inefficient and expensive to run, should only be used if there are
no other alternatives. Radiant heaters can be useful in bathrooms (e.g. heat lamps in Tastics).
Wood heaters: come in a variety of forms including open fireplaces, slow combustion stoves and
pellet heaters. Fireplaces are very energy inefficient, while slow combustion stoves create a large
volume of unhealthy fine particle pollution. Sourcing sustainable wood can be an issue. In a
residential development like Googong, try to avoid wood as the primary source of heating.
How to use heating
There are five determinants of heating costs:
1. The efficiency of the building at retaining heat: invest in high levels of insulation, draught
sealing, and even passive solar design if possible.
2. The efficiency of the heater: always buy the most efficient heater you can afford!
3. The space the heater has to heat: minimise space heated using room heaters or zoning.
4. The length of time the heater operates: use heaters only when you are home and benefiting
from the heat. Turn them off overnight and during the day when not home. Use a timer
switch to turn the heater on before you get up and before you get home!
5. The heater’s thermostat setting: 16-20°C is comfortable for most, every degree you increase
the thermostat will increase your heating costs by 5-10%.
For more detailed information: http://www.yourhome.gov.au/energy/heating-and-cooling.
5. Hot water heating – the second-largest energy user in cold climates
Hot water on demand is one of the great luxuries of modern civilisation, and choosing an efficient hot
water heater is also important. Hot water heating uses the second most energy after space heating
in a typical cold climate household, and hot water heaters usually last 15 years or longer, so choosing
an inefficient model will cost you a lot of extra energy and money over the lifetime of the heater.
Some hot water basics
When designing your home consider where you put the wet areas that will require hot water. It is
best to group these areas together as much as possible, and situate the hot water heater nearby to
reduce pipe run. This minimises installation cost, saves a huge quantity of so called ‘dead water’
(remnant cold water in hot water pipes that is wasted while waiting for new hot water to arrive),
and means that hot water will be delivered at close to the temperature it leaves the hot water
heater. Another way to deal with dead water is a dead water diverter4.
If most wet areas are grouped together but there is one distant wet area, such as an ensuite,
consider a separate instant hot water heater for the ensuite. Also, always insulate hot water pipes
all the way from heater to tap. It is mandatory to install at least three-star showerheads and fittings
in Googong, and these fittings will help you to save a lot of water and energy.
There are regulations for the storage temperature of hot water (60°C) to limit the risk of Legionella
bacteria, and also the delivery temperature of hot water (50°C) to reduce the risk of scalding.
Discuss these issues with your plumber for more information.
Types of hot water heater
Water takes a lot of energy to heat, so hot water heaters are powerful appliances that use large
quantities of energy. It is important to select a hot water heater that effectively delivers the volume
of hot water your household demands, but does so using as little energy as possible. Selecting an
efficient hot water heater is a great way to help reduce your energy bills.
Hot water heaters are classified according to both the energy source they use and whether the hot
water is stored or produced when needed (usually called ‘ instant’, ‘on demand’ or ‘continuous’).
Since a typical household usually requires hot water for only an hour or two per day, instant hot
water heaters are much more efficient than storage hot water heaters – storage tanks are effectively
large kettles that run 24 hours a day with the thermostat set to 60°C5, whereas instant hot water
heaters only produce hot water when needed. Solar hot water heaters are an exception to this rule.
Solar hot water heaters are the most efficient kind of hot water heating because in Googong 5080% of the energy used to heat the water comes free from the Sun, depending on how much water
the household uses. During the day water is warmed by sunlight and
recirculated through an insulated storage tank to keep it hot. If
necessary, an electric or gas booster increases the hot water
temperature at night, or when there has been an extended period of
cloudy weather.
An electric booster is usually an element in the tank, whereas a gas
booster is a separate gas instantaneous hot water system. Gas boosting
is more efficient than electrical boosting since the latter sometimes
Picture 1: evacuated tube solar
operates when not needed. It is a good idea to turn off electrical
4
5
...such as: http://www.redwater.net.au/ although there are a number of brands on the market.
This is the government-mandated temperature for hot water tanks to reduce Legionella risk.
boosters during the warmer months – make sure a cutoff and/or timer switch is installed for
electrically boosted systems. Also, buy a model designed for sub-zero temperatures to avoid
damage on cold nights.
There are two kinds of solar hot water heaters: flat panel and evacuated tube. Both do a good job,
although evacuated tubes are more efficient (and usually more expensive) than flat panels. The
solar panels/tubes must have access to the Sun, so they should face north and be un-shadowed by
trees or buildings and meet Googong design requirements. There is a rebate available for installing a
solar hot water heater under the Small Scale Renewable Energy Scheme6.
Gas (and electric) instant hot water heaters heat water only as you need
it, and they never run out of hot water. Gas instant hot water heaters are
now very common in the Capital Region because they are far more
efficient than storage tanks. Separate controllers can be installed at each
hot water tap, so each controller can be programmed to deliver water at a
given temperature, which can eliminate the need for mixing with cold
water, saving energy and reducing risk of scalding. In the past, instant hot
water heaters have sometimes had problems with low flow showerheads,
so make sure to install an appropriate model that can deliver hot water at
low flow rates. Electric instantaneous hot water heaters powerful enough
to service a house require three-phase power and are very uncommon
here, but they do exist7.
Picture 2: instantaneous gas
Heat pump storage hot water heaters operate on the same principle as reverse cycle airconditioners – they use electricity to draw extra energy from the outside air. This means they are
significantly more efficient than standard electrical or gas storage tanks, although their efficiency
decreases with the temperature of the outside air. If you buy a heat pump, make sure to purchase a
model that is suitable for the sub-zero conditions of Googong winters, and try to site it on the
northern side of the house where the air will be warmest in winter. Noise can also be an issue for
heat pump hot water heaters, so think carefully about the effect of noise on you and your
neighbours before buying one. There is a rebate available for installing a heat pump under the Small
Scale Renewable Energy Scheme8.
Storage tank hot water heaters are the cheapest hot water heaters upfront, but also by far the least
efficient, which means they are expensive to run. Tanks come in a range of sizes and can be heated
by electricity or gas. If you buy a storage tank hot water heater make sure to size it appropriately for
your needs because oversized tanks cost significantly more to run for no benefit. Try to avoid
storage tank hot water heaters and buy a solar or instant system instead.
Hot water behaviour
Most hot water is used in the bathroom for showering, baths and hand washing, followed by the
laundry and kitchen. Purchase the most water efficient appliances possible, and reflect upon
behaviours like showering time, clothes washing temperature, how you use the dishwasher, etc.
because wasted hot water results in wasted water, energy and money from your pocket.
For more detailed information: http://www.yourhome.gov.au/energy/hot-water-service.
6
See here: http://ret.cleanenergyregulator.gov.au/hot-water-systems.
.For example: http://www.stiebel.com.au/water-heating#instant-hot-water-system-3-phase-electric.
8
See here: http://ret.cleanenergyregulator.gov.au/hot-water-systems.
7
6. Balancing the double-edged sword of windows
A house without windows is a bunker, and no one wants to live in one of those, so glazing is an
essential part of any house. Windows have some wonderful benefits – they let in light, enable views,
and enhance the feeling of space in a room – but they also have downsides which must be carefully
managed to maintain energy efficiency.
Windows are composed of two main elements: the glazing, which is the kind of glass in the window,
and the framing, which holds the glass in place. Both window elements are important for energy
efficiency because both can lose heat very rapidly in a cold climate like Googong’s – in extreme
cases, up to 40% of heat loss from a house in winter can be through the windows!
There are other aspects to windows that also should be carefully considered, such as how many and
what size they should be, which directions they should face, whether they require solar access in
winter or shading in summer, and whether tinting is appropriate.
Energy efficiency and windows – positives and negatives
On the positive side, north-facing windows allow a lot of sunlight in during winter which can warm a
house during the day and, if used in conjunction with thermal mass, can even help to keep it warm
on cold winter nights. On the other hand, sunlight through windows in summer can rapidly overheat
a well sealed and insulated house, so it is important to block sunlight from striking the glass during
the summer using eaves or other external shading devices (see Shading).
On the negative side, windows are very poor insulators,
so they allow a lot of heat to conduct in and out of the
house. In winter, when single glazing has a similar
temperature to the outside air, windows also create
convection currents (see figure 1), cooling the warm air
that flows past them and creating cold draughts at floor
level. Some windows can also become leaky, especially
after a significant period of use, which makes them a
potential vulnerability in a well sealed house.
Figure 1: cold window creating convection current
R-values and U-values
Unlike insulation and other building products where R-values (resistance to heat flow) are used to
denote insulating effectiveness, window manufacturers use U-values, the inverse of R-values
(U=1/R). U-values tell you how quickly a window will conduct heat. Do not make the mistake of
buying a window with a high U-value – with U values, the LOWER the better.
WERS – the Windows Energy Rating Scheme
It is a requirement that all windows for sale in Australia are tested on a range of qualities: U-value
(Uw on WERS, the rate at which a window conducts heat), Solar Heat Game Coefficient (SHGC, the
amount of heat in sunlight that passes through a window, measured 0-1, higher means more heat),
Tvw (visible light transmittance, measured 0-1, higher means more light), and AI (air infiltration, how
well a window seals). Test results are published on the WERS website (http://www.wers.net/wershome). WERS also has a useful star rating system for the effectiveness of each window in terms of
heating (keeping the heat in) and cooling (keeping the heat out).
Different kinds of glazing
Single glazing has been standard in Australian housing for as long as Australians have built houses,
however it is not suitable in cold climates like Googong. Glass has minimal insulation properties, so
single glazed windows are roughly the same temperature as the outside air. As a consequence, in
winter single glazing creates large cold surfaces in rooms with external windows, and conduct heat
out of the house rapidly, as well as creating uncomfortable convection currents. Single glazing can
also cause condensation issues due to the low temperature of the glass. Single glazing typically has
U-values of 5 or higher (R-values of 0.20 or lower).
Double glazing, which consists of two panes of glass either side of a gap usually filled with argon gas
or a vacuum, is becoming increasingly popular in new housing and renovations in Australia. It is
significantly more insulating than single glazing, and acts to keep the interior pane of glass at a
temperature closer to that of the inside air, reducing conductive heat loss and the likelihood of
potential condensation problems.
For maximum effect, framing of double- (and triple-) glazing should be thermally broken aluminium,
timber or uPVC, and the glazing gap should be 12-16mm. Not all double glazing is equal, and there
is a wide range of U-values for double glazing from 1.4-6.4 (R-values of 0.71 down to 0.16), so it is a
good idea to carefully check your double glazing on WERS to make sure you are getting what you pay
for: a U-value of 3.0 or lower is a reasonable expectation from double glazing.
Triple glazing is similar to double glazing except there are three panes of glass and two gaps. Like
double glazing, not all triple glazing is equal: U-values range from 0.8-4.0 (R-values of1.25-0.25; an
R1.25 window is incredible, but expensive! You get what you pay for in glazing). If you are going to
pay a premium for triple glazing, expect a U-value of 2.0 or lower.
Secondary glazing consists of various systems used to attach a
secondary window pane to an existing single glazed window, which
usually involve a secondary frame or attachment via magnets.
Some secondary glazing is quite effective, with U values ranging
from 1.5-4.7 (R-values of 0.67-0.21).
Glazing treatments
Low emissivity glass has a coating applied to the inside of the glazing in the factory. This helps to
reflect radiant heat back into the house, improving the glazing's performance as an insulator and
lowering the window’s U-value. Low emissivity glass is often combined with double or triple glazing.
Tinting can be used to reduce heat gain or visible light transmittance through a window from
sunlight, however it should be used with caution. External shading is often a better solution if the
problem is summer heat gain. Tinting to reduce heat gain should definitely not be used on northfacing windows as that will reduce passive solar heat gain during winter. Tinting on east-, west- and
south-facing windows is less problematic and can be useful in some situations.
Window coverings
It is vital to install window coverings designed for insulating to keep the heat inside, and prevent
convection currents, on freezing Googong nights. There are two kinds:
1. multi-layered curtains (at least two separate layers of fabric, preferably with a layer of
insulating wadding in between) with a box or blind pelmet, sealed to the architrave at the
sides with velcro, and just touching the floor, so as to trap cold air next to the window, or,
2. honeycomb blinds fitted inside the window reveals and bracketed to stop air leakage.
For more detailed information: http://www.yourhome.gov.au/passive-design/glazing.
The importance of framing
Window framing is often forgotten, but it is a very important part of any window. In a cold climate,
standard aluminium framing loses heat very rapidly during winter. The nature of the framing also
contributes to how well it seals. Double and triple glazing should always be installed in conjunction
with insulating framing such as thermally broken aluminium, timber or uPVC, because standard
aluminium framing significantly reduces the effectiveness of the expensive glazing.
7. Understanding energy – basics for homeowners
The most powerful tool you can use to reduce your energy consumption and maximise your energy
efficiency is to understand energy, especially how it is measured, and how quickly particular
appliances and activities consume it. Understanding the basics of energy will give you power over
your energy consumption.
Household energy consumption
In a cold region like Googong –
technically referred to as a
‘heating climate’ – most
household energy consumption
goes to space heating, followed
by hot water heating.
Combined, these two activities
typically account for 80% or
more of a household’s total
annual energy consumption9.
Appliance use, lighting and
cooking make up the rest.
The best way to think about household energy consumption is to break it down into two
components:
1. passive household energy consumption, the rate at which the building use energy due to its
design, level of insulation and draught sealing, and fittings; and the efficiency of the heater,
hot water heater, lighting, appliances and standby power consumption; and,
2. active household energy consumption, which derives from occupants turning things on (and
off!), and is based on household behaviour and level of energy consciousness.
Minimising passive household energy consumption is about designing and building your home so
that it passively uses less energy than a typical house for important tasks like heating and cooling,
hot water heating, lighting, refrigeration, cooking, clothes washing, and entertainment. This involves
investing in the most efficient building and appliances you can afford.
Minimising active energy consumption is all about conscious behaviour towards energy -using
devices: using heating moderately and only when you are benefiting from it (i.e. not overnight or
during the day if you are not there), using hot water consciously, turning off lighting and appliances
when they are not in use, turning off appliances at the socket to minimise standby power, etc.
Household energy consumption – some detail
There are some important units of measurement that you may have heard of but may not
understand. They are explained below.
Watts (W) and kilowatts (kW): the RATE at which an appliance uses electrcity (or a photovoltaic
solar panel produces electricity). A kilowatt is 1000W, just like a kilogram is 1000g or a kilometre
1000m. So, if you know the wattage of an appliance but need the kilowattage, divide the wattage by
1000!
9
This is an approximate figure and assumes a house with a storage tank hot water heater. Patterns of energy consumption
vary from household to household due to a wide range of factors.
Kilowatt hour (kWh): a TOTAL QUANTITY of electricity. The number below the ‘kWh’ column on
your electricity bill tells you how many kilowatt hours were consumed by all of the appliances used
by your household during that billing period. The price of electricity currently ranges from about 2040c/kWh depending on your location and contract.
If you know the wattage of an appliance, and how long it is on for, you can roughly calculate the
total quantity of electricity used by the appliance using these equations:
rate (W) x time (h)= total (Wh)
rate (kW) x time (h)= total (kWh)
Examples:
 a 100W appliance, such as a small-medium sized LED television or laptop, running for 10
hours, would use (100x10=)1000Wh or 1kWh
 a 1000W hotplate running for one hour would use (1000x1)=1000Wh or 1kWh;
 a 4kW heater running for 15 minutes would also use (4x0.25=)1kWh.
Megajoules (MJ): a total quantity of energy. The number below the ‘MJ’ column on your gas bill
tells you how many megajoules of gas were consumed by all of the gas appliances used by your
household during that billing period. The price of a megajoule of residential gas currently ranges
from about 2.2-3.0c/MJ depending on your location and contract. The rate at which gas heaters
consume gas is quoted in MJ/hr.
If you need to, you can convert between kilowatt hours and megajoules since they are both
quantities of energy:
1kWh = 3.6MJ
Greenhouse gas emissions: as a rough rule of thumb, 1kWh of electricity from the grid generates
about 1kg of carbon dioxide in NSW/ACT. This number varies from State to State depending on the
predominant source of the power generation (black coal, brown coal, natural gas, wind, solar). If
you choose to buy Green Power, this number drops to close to zero carbon dioxide emissions
because you are effectively buying your power from the share of the grid that is renewable.
R-value (and U-value): Every building element – ceiling, walls, windows, doors, and floor – has an Rvalue: its resistance to transmission of heat. The higher the R-value the better because that
translates to more resistance to heat loss in winter (and conductive gain in summer). In this climate,
some desirable R-values are:
ceiling batts – R5
floor batts – R2.5
windows – R0.33 (double glazed, lowconduction framing)
wall total – R3 (R2.5 batts +wall itself)
doors – most doors do not quote R-values in
specifications
U-values are the inverse of R values (U=1/R): they measure how quickly heat is transmitted through
a building element. U-values are typically quoted for windows, while R-values are usually quoted for
everything else. The lower the U-value, the less heat is transmitted through a window, so when
shopping for windows the lower the U-value the better.
Standby power: many appliances use power even when they are NOT ON! Every 10W of standby
power around the house equates to about 80kWh/yr10 (about $32/yr11 in Googong!) of electricity
consumed for no benefit, so it is a good idea to turn off all appliances at the power socket when not
in use. If you cannot reach the socket, try using wireless remote switches or timer switches.
10
11
(10x24x365) = 87.6kWh/yr, -10% for operational time.
80x0.40c=$32
8. SITE SELECTION
Site Orientation
Choosing the right site for your home is the single most important decision you can make in
setting up the optimum conditions for a sustainable house. The climate in Googong makes it
important to obtain as much advantage as possible from the warming effect of the sun, and
the orientation of your block will facilitate this.
True North
Ideally your site will face true north, with its long axis running as close to true east-west as
possible. This will make it easier for your designer to gain the most benefit from the sun to
provide warmth and energy for your home.
20˚E
15˚W
15˚W
20˚E
A slight deviation from true north can be accommodated without significant loss of solar
access.
Fortunately, the majority of building sites at Googong have a northern orientation which will
make it easier to orient your building to capitalise on solar energy.
Diagram showing one example of lot orientation at Googong
The position of the building on the site and the internal layout of the house in relation to the
orientation of the site will vary from site to site depending on the direction of true north,
the position of the road relative to the building and the location of adjacent structures.
Site Elevation
An elevated site will make it easier to capture cooling breezes in summer time whilst
providing views over the development to the hills and landscape beyond.
Drainage will also be assisted by an elevated site, especially those sites which are above the
street level, as this will facilitate drainage to the street stormwater system.
Building Position
It is tempting, and quite often done, to build on the best part of the site, however it is better
to build on those parts of the site which are in the worst condition as the act of building will
help repair that part of the site and the outlook from the building will then be to the most
beautiful part of the site.
Building Orientation
W
E
The building should face as close as possible to true north, with the long axis of the house
running true east-west (like the site) with the ratio of length to width illustrated above, as
this will enable as many rooms and spaces as possible to face north.
Wind and weather patterns
Observe the direction of prevailing winds and weather in relation to the site to determine
the best location for windows, shade and shelter. Position windows, doors and other
openings to maximise the benefit from cooling breezes in summer but provide protection
from harsh winter winds.
Neighbouring structures and solar access
Street
Take note of neighbouring structures, whether natural (eg trees and other landscaping) or
man-made (buildings) and the impact they may have on the solar access of your site and the
wind and weather patterns. Tall trees or other structures to the north of your building site
will impact on the availability of solar energy, but may also help in providing shade in
summer and shelter from weather.
Zoning
Areas in the house where you will spend most of your time, apart from sleeping, will be best
positioned on the northern side of the house as this will provide the best conditions for
comfort. Areas where activities don’t require similar levels of comfort (eg bedrooms,
laundry, toilets etc) can be positioned on the south, east and west sides of the house.
9. ENERGY EFFICIENCY
Energy Efficiency is the single most effective way of reducing energy consumption and cost
in the design and operation of your home. It applies to:



Building design (see also Passive Solar Design fact sheet)
Appliances and other energy users (space heating and cooling, hot water systems,
lighting)
Operational energy demand (for lighting, heating, cooling, ventilation, appliances)
Building Design (see the Passive Solar Design fact sheet)
1
2
3
4
5
6
7
8
9
10
Site location
Orientation for direct solar gain
Zoning for thermal efficiency
Thermal mass
Insulation
Ventilation
Glazing for direct solar gain
Sealing of draughts
Shade
Landscaping
Energy Efficient Appliances
The type of appliances you chose and how you use them will have a big impact on the
energy savings achieved in your home. Appliances include TVs, home entertainment
systems, refrigerators, washing machines, dishwashers, blenders, grinders, mixers, irons etc.
The energy efficiency of appliances is required to be stated on the Energy Star label
attached to the appliance and this star rating describes the performance of the appliance in
relation to its energy efficiency. Appliances with a higher star rating use less energy and
produce less greenhouse gas emissions. The average annual consumption for the appliance
is stated in kWh per year.
The size of an appliance can also have an impact on its energy consumption, even if it has a
high star rating, so choose the size of the appliance most appropriate for your needs.
Modern high tech electronic equipment is often fitted with a standby mode making it
convenient to start up instantly when required. Unfortunately, in the standby mode, the
appliance still consumes electricity, which can amount to 10-12% of its normal use, so it is
important to ensure appliances are turned off at the power point.
A ’Green Switch’ is a wireless home energy control system which will help manage standby
power use by making it easy to switch off appliances that are not in use.
A green switch comprises two units – a small portable remote control unit and a small
‘slave’ unit which plugs into the 240V wall socket, into which an appliance is plugged. The
appliance can then be turned on and off using the remote control unit.
An alternative to a green switch is a ‘Master Control Switch’ which is a switch that can be
installed over nominated circuits (power and lighting) to enable the fittings on the
nominated circuits to be all switched off at once. For instance, when retiring at night, all
lights and appliances in the house that are on (or are on standby) can be turned off from the
one conveniently located position.
Ask your builder to install a Master Control Switch over nominated power and lighting
circuits.
A ‘Smart Meter’ is normally installed by the electricity supply company and provides data
that enable customers to make choices about how much energy they use by providing them
with accurate real-time information about their electricity consumption.
Space Heating
In the cool climate of Googong, heating will most likely represent the majority of your
energy consumption, so install the most efficient heating system available and ensure that
the heat you generate is retained within the building by the use of thermal mass, insulation
and draught sealing (see Passive Solar Design factsheet).
The amount of heating you need depends on many things, including your home’s star rating,
extent of draughts and microclimate.
Options for space heating to achieve a comfortable home include:






Solar Hydronic
Solar to air
Reverse cycle air conditioning
Electric
Gas
Solid fuel
Hot Water
Hot water is the next largest energy user after space heating. Purchase the most energy
efficient hot water system available and ensure that it is positioned to maximise solar gain
while minimising heat loss from the storage tank itself and from the pipework taking the
heated water to delivery points.
The choice of the most appropriate system is detailed on the Hot Water fact sheet. An
evacuated tube system would provide the most efficient water heating system in a location
such as Googong as such a system will extract the maximum heat from the available
sunlight.
Locating the system close to outlets is important to minimise runs to delivery points, so
locating bathrooms close together can assist to reduce heat loss in pipework. Insulating the
pipework will assist in retaining the valuable heat energy generated by the collector panel.
Lighting
Advances in lighting technology mean that energy efficient lighting is possible with no
sacrifice in lighting quality. Older style incandescent light fittings which produced a
significant amount of heat have been replaced by compact fluorescent and LED lamps with
significant savings in energy consumption.
LED lamps in particular can reduce energy consumption by up to 70% compared to
incandescent fittings and have lifetimes of 50,000 hours which make their initial cost more
acceptable over the long term. LED lamps are also more reliable, efficient and operate at
safe low voltages.
Lighting Plan
A lighting plan comprising natural daylight, low energy light fittings, lighting control systems
and innovative circuitry can:






Provide a high level of visual comfort
Use daylight via windows, skylights, skytubes and clerestory windows where
appropriate
Have low energy requirements
Include motion sensors for limiting the time lights are on and turn off when not
required
Highlight the architecture and design
Minimise consumption by designing circuits so that only lights that are needed are
switched on
Operational energy demand
The amount of energy consumed in your home will depend on a number of factors, not the
least of which is the amount of time appliances, lights, air conditioning and heaters are
switched on or left in standby mode, ready to leap into action in the blink of an eye.
Motion sensors and timers can save a lot of energy where, for instance, lights will only turn
on when you enter a room or space controlled by the motion sensor. Lights will remain on
as long as the person is in the room. The time length of the sensor can be adjusted to suit
the activity.
As previously mentioned, forgetting to turn off appliances at the main power point can also
contribute to significant ‘phantom’ energy use, which can amount to 10-12% of the
appliance consumption.
Control systems and power management
Understanding your home energy use is a first step to managing and potentially reducing
your energy consumption. A simple way to start coming to grips with your consumption
patterns is to install a power usage meter which lets you measure energy use and calculate
the running costs of different appliances as well as their greenhouse gas emissions.
Knowing which appliances consume the most electricity will help you choose when to use
them based on the electricity rate at the particular time you plan to use them. For example,
you may choose to use your washing machine during off-peak times when electricity is
cheapest.
Wireless meters let you take readings without having to access the main socket unit.
More sophisticated (and expensive) systems operate as ‘data loggers’ which will monitor
energy use over a range of appliances, including air conditioning systems. This type of
system will be useful, to those seeking to make serious changes to their usage patterns.
Rating Tools
There are a number of house energy rating and modeling tools available in Australia for
carrying out assessments of the thermal performance of proposed buildings. At present
there are no accredited tools which measure overall environmental performance.
The accredited tools which have been developed to assess thermal performance include:
BERS
Building Energy Rating Scheme, which is more applicable to tropical and
subtropical climates
NatHERS
National House Energy Rating Scheme is the framework tool used to assess
thermal performance of house designs against minimum compliance
standards set by the BCA (Building Code of Australia)
AccuRate
Developed for thermal assessment in the ACT, now the standard tool for
thermal assessment of residential buildings in Australia
First Rate
Developed by the Victorian Government for use in Victoria
Ratings prepared by accredited assessors using the above tools are accepted by most
authorities in Australia.
Using one of the above rating tools will enable the inclusion of factors which will facilitate
the design of higher star rated buildings, with the potential for significant energy and water
savings.
In NSW, new houses are required to meet minimum energy and water reductions mandated
under the Government’s BASIX compliance scheme, which requires reductions of 40% in
water and 40% in energy compared to standard houses. Houses in Googong are required to
meet the stricter requirement of a 50% reduction in water use as part of the DA process.
The rating tools produce a ‘star rating’ which indicates the thermal performance of the
building in its requirement for heating and cooling within a range or ‘band’ of energy
consumption, measured in MJ/m2 per annum, required to achieve comfort levels as follows:
Star Rating
1
2
3
4
5
6
7
8
9
10
Annual MJ/m2
heating and cooling
284
186
125
88
66
51
39
26
14
5
Recent research * by the CSIRO found that building a 5-star rated dwelling will provide
improved thermal comfort whilst saving money both during construction and occupancy.
Links
NatHERS
www.nathers.gov.au
BASIX
www.basix.nsw.gov.au/basixcms
CSIROwww.industry.gov.au/Energy/Pages/Evaluation5StarEEfficiencyStandardResidentialBu
ildings.aspx
10. GREEN MATERIALS = HEALTHY MATERIALS
All materials used in building construction will have an impact on the environment and
potentially your health ranging from relatively benign to reasonably toxic.
To be considered ‘green’, healthy or ‘low impact’, building materials will have the following
characteristics:










Renewable and abundant, low resource depletion
Low embodied energy
Non polluting
Durable
Recyclable and able to be re-used
High recycled content
Minimal impact on air and water quality
Non-hazardous formulation (avoiding constituents such as formaldehyde, PVC)
Equitable, local production
3rd party accreditation
Materials which are renewable and abundant will incur minimal resource depletion and
come from diverse natural sources whose production has a low impact on the environment.
Low resource depletion materials include mud brick, rammed earth, reinforcing steel,
particle board and plywood whereas materials requiring substantial resource extraction
include metals (copper, aluminium) and plastics.
Embodied energy is the energy used to extract, transport, manufacture and fix in place.
Metals used in building (eg copper pipe and sheet, aluminium extrusions) and some plastics
(eg PVC pipes, ducts and conduits) have high embodied energy, whereas materials such as
mud bricks, rammed earth, clay bricks and timber products have low embodied energy.
Durable materials will last longer performing their required function than inferior, cheaper
materials and will therefore not require replacement for much longer.
Materials which are recyclable will have another life when they have finished their current
function, so will reduce the need for new materials to be created. This also applies to how
materials are fixed into a building, for example bolting members together can facilitate later
re-use without damaging the original material.
Materials with a high recycled content include recycled timber (which can be 100%
recycled), ‘green’ concrete with a cement substitute and a recycled aggregate content,
building boards made from timber waste with a binding agent, steel reinforcement made
from scrap metal.
Materials which ‘off-gas’ or emit harmful vapours, particles or toxins into the environment
due to their manufacturing processes will have an impact on air quality over a long period of
time, often resulting in VOCs (volatile organic compounds) being released into the
atmosphere well after the material has been fixed in place. Other materials, such as lead
flashing, can contaminate the soil and waterways by carrying lead particles in rainwater.
This is amply demonstrated where lead flashing is used in conjunction with galvanised
gutters resulting in corrosion of the gutters due to the galvanic reaction between the lead
runoff in rainwater and the zinc in the galvanised gutters.
Materials with a non-hazardous formulation present no risk to builders or users by virtue of
the nature of their constituent materials. E0 MDF (zero emission medium density
fibreboard) boards for example use no toxic glues in their manufacture, so they don’t off-gas
during use and present no problem to fabricators working with the material (cutting,
sanding, drilling etc).
Where possible, materials which are derived and produced ethically via socially fair means
and through local production will maximise equitability and local employment whilst
minimising the environmental impact by virtue of the shorter distances required to
transport the material in both raw and manufactured states.
3rd party accreditation organisations will attest to
the environmental impacts of mainly timber
materials, eg the Australian Forestry Standard
(AFS) and the Forest Stewardship Council (FSC)
organisations which certify timber as being a
single species from a managed resource, a mixture
of species from managed resources or recycled
material.
The following list comprises preferred materials with a low environmental impact:

















Timber products generally, with AFS or FSC certification
Recycled solid timber
Plantation timber for framing, lining and cladding
Green concrete with 40% less cement and 60% recycled aggregate
Stone (sandstone, limestone, granite, marble)
Natural insulation such as wool, mineral wool, paper
Hay bales
Straw based wall panels
Cork, linoleum
HDPE (high density polyethylene) drainage pipes
Stainless steel mesh termite management
Clay brick and tile
Terra cotta
Double and triple glazing in a timber or thermally isolated aluminium frame
Zero emission MDF board (E0 MDF)
Plant based oils, paints and, stains and beeswax
Polyethylene electrical and data cables
The following are examples of materials which have positive ecological properties and
contribute to a healthy environment both during construction and occupation.
Drainage pipes
HDPE (High Density Polyethylene) drainage pipes
Adhesives and tile grout
Non-polyurethane or formaldehyde based adhesives for carpentry and timber joinery
generally
Paints, oils and stains
Plant based paints with no VOCs (volatile organic compounds) for both interior and exterior
use. Linseed oil based finishes and natural waxes protect and enhance the life and
appearance of timber
Joinery
Cupboard carcasses and other joinery items constructed from E0 MDF boards (zero
emission, medium density fibre board) are VOC-free.
Ecoply plywood uses VOC free adhesives
Non chemical pest control
The only non-chemical system for managing termites is a stainless steel mesh barrier
(‘Termimesh’).
Where cost is a significant factor, low-impact chemical membranes which are impregnated
with chemicals (eg ‘HomeGuard’ and ‘Kordon’) are approved under the Building Code of
Australia for termite management.
Chemical spray/saturation techniques are also approved under the BCA but are to be
avoided as the chemical residue remains in the soil for a considerable period after
application and requires regular re-application.
Indoor Environment Quality-Sick Building Syndrome
Unhealthy/toxic materials pose a risk both to the environment and to those who use the
materials as well as those who live within them. As buildings have become more airtight for
energy efficiency reasons, so has the need to minimise the amount of emissions from
building and furnishing materials released into the interior environment.
When chemicals build up in the internal environment and there is a lack of ventilation, sick
building syndrome can develop, potentially causing headaches, fatigue, sleepiness, loss of
concentration, nausea. This can be exacerbated by the type of lighting employed, the
temperature and humidity of the air and factors relating to ability to control the indoor
environment.
The following materials are unhealthy - some dangerously so and should be avoided:


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




Asbestos
Lead
Lead cadmium
Mercury
Chlorinated polyethylene
Chlorosulphonated polyethylene
Petrochemical fertilisers and pesticides
Chlorofluorocarbons (CFCs)
Phthalates chloroprene (neoprene)
Polyvinyl chloride (PVC)
Formaldehyde
Wood treatments containing creosote, arsenic, cyanide or pentachlorophenal
Halogenated flame retardants
11. LIGHTING
Lighting includes both natural and artificial light and the design of a lighting system will form an
integral part of the overall sustainable design approach.
On average, lighting your home makes up 5-10% of your electricity bill, so increasing the energy
efficiency of your lighting system will improve the overall energy efficiency of your home.
An efficient lighting system will:
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Make use of natural light, so living areas including kitchen and bedrooms don’t require any
artificial lighting during the day
Provide a high level of visual comfort
Allow the efficient performance of a visual task
Provide the best light for the task (how bright is bright enough)
Provide controls for flexibility to minimize the number of lights required in a space and the
amount of time they are on through the use of motion detectors and timers, for instance
Have low energy requirements by selection of energy efficient lights and lamps
Create an atmosphere or ambience
Daylight
Sunlight is used (see passive solar design fact sheet) to provide both warmth to the interior of a
house and light for daily tasks. Glazed windows, clerestory windows and skylights admit light to the
internal spaces of buildings, and insulation in windows, walls, floor and roof provide the means to
retain the warmth, whilst the position of windows and internal colour selection will assist in
optimizing the use of daylight.
Glare arising from bright sunlight falling on work surfaces forms a distraction, reduces attention and
causes fatigue to the eye. Glare can be avoided by carefully positioned external fixed shading and/or
adjustable shading devices such as operable louvres, blinds and awnings.
Lighting Layout
Artificial lighting will provide lighting for those tasks where natural daylight is insufficient and at
night. The layout of your lighting system will have a big impact on the comfort of the tasks and the
energy consumption associated with them.
With the advent of low-wattage light fittings, such as CFLs (compact fluorescent lights) and LEDs
(light emitting diodes), it is possible to design your lighting to minimize the number of lights turned
on at any particular time and provide task lighting where, in the past, lighting of whole spaces was
required to provide an adequate level of illumination for tasks and comfort.
This is not to be confused with ‘low voltage’ light fittings such as halogens, which provide more heat
than light and contribute to excessive energy use.
Allow for lights which are not used for long periods to be fitted with a sensor to detect movement
and switch on for a short period and turn off automatically. Timers can also be used to activate lights
as a security measure when you are away from the house for any length of time.
Install a ‘Master Control Switch’ over nominated lighting circuits to enable fittings on these
circuits to be all switched off at once.
Light fittings
Incandescent fittings produce light by heating a metal filament, which causes a lot of heat to be lost
in generating light, consequently this type of fitting is no longer legally manufactured for sale in
Australia except for stock which was made before the legislation came into force.
Traditional halogen bulbs also create lots of heat, which means that ceiling insulation must stay clear
of down lights to avoid the risk of fire and this degrades the effectiveness of the insulation, which
leads to significant heat loss through the roof space.
LED down lights however, produce almost no heat, and many types can be ‘capped’ – meaning you
can run your ceiling insulation right over the top of them.
Ask your builder to recommend LED light styles.
This graph shows the improving efficiency of different lighting technologies over time. You can see
that to generate the for same amount of light, a Halogen uses 60W, whereas an LED uses 4-5W
12. VENTILATION AND COOLING
Natural ventilation
Natural ventilation relies on natural air movement and is primarily associated with the
provision of adequate cooling in summer. It can save significant amounts of fossil fuel based
energy by reducing the need for mechanical ventilation and air-conditioning.
The principal factors affecting natural air movement around and within buildings are:
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The site and local landscaping features
The building form, orientation and envelope design, including position and size of
openings
The internal planning of the building and room design
Influence of site and landscaping features
Local factors, such as wind conditions, topographic features such as hills, ridges and
escarpments and landscaping elements such as trees, shelter belts and shrubs will influence
the way air moves around the site. Local wind speeds can be estimated from Bureau of
Meteorology wind data which needs to be moderated for the abovementioned local factors.
In summer, the ideal would be for light winds to provide sufficient internal air movement for
thermal comfort during all but extreme conditions and for night time cooling of the building
(‘night purging’).
The problem for temperate and cold climates in winter is to avoid excessive wind through
ventilation openings and leaks in the building envelope.
Vegetation can help modify the external wind direction so as to enhance ventilation as well
as cool incoming air. Dense shrubs and tree canopies should be kept clear of windows and
other openings to minimise obstruction to air movement.
Summer
Winter
Passive cooling
Passive solar heating with
active heating from roof space
Sketches of summer passive cooling and winter passive solar heating and active heating
from roof space
The main design elements for passive cooling of buildings in a climate like Googong are:
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Orientation for exposure to cooling breezes
Increase natural ventilation
Effective shading to reduce heat load
Adequate levels of insulation
Floor plan zoning to maximise comfort for daytime activities and sleeping comfort
Appropriate windows and glazing to minimise unwanted heat gains and maximise
ventilation
Landscaping for shade and cooling
High thermal mass construction (see Passive Solar Design fact sheet)
The building form, orientation, envelope design and window openings
Naturally ventilated buildings should be oriented to maximise their exposure to the
prevailing (summer) wind direction, with a relatively narrow plan form to facilitate the
passage of air through the building (cross ventilation). Passive solar requirements (see
Passive Solar Design fact sheet) will need to be optimised with ventilation requirements so
both can contribute to thermal comfort.
French doors
and wing wall
Casement
sashes to
catch breeze
Prevailing breeze
French doors with
one leaf wall fixed
Awning sashes
Image courtesy Dick Aynsely Environment Design Guide
Windows should be located to receive the prevailing wind for summer conditions and
should ideally be installed on both sides of occupied spaces for cross ventilation. The total
area of windows on the outlet side of the building should be bigger than those on the inlet
side to facilitate air movement.
Passive-design shade (eaves, roof overhang, awnings) will limit heat build-up in summer and
admit the sun in winter.
Different window styles and sizes will provide varying ventilation rates. See diagram below.
Horizontal &
vertical sliding
Louvres
Casement
Awning
Bi fold
Different window styles offer different ventilation outcomes
Louvre windows offer almost 100% opening area. Casement windows with friction stays can
be up to 60% more efficient than other sash types or sliding doors on the windward side.
Sliding windows can be problematic in that they can only be opened half way and can’t be
adjusted according to wind direction.
Short ‘wing walls’ can increase air flow through windows when the prevailing wind is not
perpendicular to the window wall.
Internal planning and room layout
Internal resistance
minimised
Outlet
Wind
Natural ventilation of a building
To facilitate the natural ventilation of rooms, the resistance to airflow through the building
needs to be minimised. Air movement will be facilitated by large openings and by reducing
the number of rooms through which the air has to pass.
Landscaping for shade and cooling
Prevention of unwanted summer heat build-up is important in reducing mechanical cooling
requirements, in particular air conditioning, and landscaping can contribute by providing
shading to buildings and ground surfaces. Care needs to be taken to ensure that shading is
not extended to solar collectors which will generally be on the roof.
Vegetation helps lower surrounding air temperature by evaporative cooling resulting from
transpiration.
Plants and grasses can also help to reduce the heat load on exposed surfaces by the
provision of a vegetative ground cover which obstructs the heating effect of solar energy.
In Googong, a minimum of 30% of the front garden area is required to be planted garden
beds, minimising reflective surfaces, which will go a long way to reducing heat load from
both direct and reflected radiant solar energy.
Carefully located planting can also be used to assist in funnelling cooling breezes into and
around the house in summer and blocking cold winter winds.
Benefits from landscaping are:
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Support for indigenous and endemic plant species and backyard food production
Improved thermal and sound insulation
Reduced heating and cooling requirements from the formation of microclimate
Reduced stormwater runoff
Increased biodiversity
Encouragement for birds and other wildlife
Amenity, aesthetics
Food Production
Using open space around the house for a vegetable garden can contribute to your food
requirements, even if you only plant some herbs.
Permaculture gardening, no-dig garden beds and ‘wicking’ beds are simple ways to start
creating a productive garden.
Your garden will benefit from the rich compost derived from a compost system or worm
farm and will help to minimise the amount of waste generated from your house.
Green Walls and Roofs
Green walls (also known as ‘Living Walls’, ‘Vertical Gardens’ etc) are particularly useful
where space is limited for a horizontal garden and if attached to a wall can help reduce the
temperature of a building by evaporative cooling through the process of transpiration.
Green walls can also help filter and purify water which can be continuously cycled through
the soil medium.
Green roofs are roofs planted with vegetation which can provide many benefits as follows:
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Reduce heat load in summer and heat loss in winter
Filter air and water pollutants
Reduce stormwater runoff
Adds thermal mass
Encourages natural habitat creation
13. WASTE MANAGEMENT
A large percentage of waste going into landfill is related to the construction, demolition and
renovation of buildings. Even more waste is produced during the occupancy of buildings
through the consumption of goods and services.
This waste constitutes not only considerable environmental degradation but also represents
a big financial burden for current and future generations.
Ask your builder to prepare a waste management plan to minimise, separate and recycle
waste generated on building sites so that:
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Waste going to landfill is minimised
Emissions, pollution and contamination are minimised
Scarce resources are protected
Construction costs are reduced
Tipping fees are reduced or negated
Design, detailing and specification stage
At the design, detailing and specification stage, make decisions which will have an impact on
cost effective waste reduction techniques. Material selection and construction detailing
strategies can have a big impact on the amount of waste material that is generated, as well
as affecting the way the building is recycled later in life.
This includes errors in documentation which necessitate rectification or replacement of
building elements incorrectly installed.
Consider the size, flexibility and adaptability of the project as this will affect the resource
use per person and consequent waste, space allowance and energy use, as well as future
recycling and/or re-use of the building and its components.
Life cycle analysis (LCA) of materials used in the construction can identify material
durability, recyclability and disposability issues as well as environmentally damaging, toxic
or waste-prone materials, which should be minimised or eliminated.
Buildings that are designed for deconstruction will consider materials and jointing methods
which permit disassembly and deconstruction which will encourage re-use and recycling.
Prefabrication of certain building elements, eg roof trusses, precast concrete elements can
eliminate on-site waste, whilst standardised work practices and full utilisation of offcuts can
further contribute to resource efficiency and waste reduction.
Modular design that accommodates standard material sizes should be the norm. This is
particularly relevant in wall linings where ceiling heights determine sheet size – perhaps it
should be the other way round. Sheets are normally supplied in 300mm increments in size
so offcuts are almost unavoidable unless the ceiling heights are 2400, 2700 or 3000mm.
Legislation, contracts, policies and Australian Standards can be barriers to greener
specifications and the incorporation of reused, recycled and reconstituted materials.
Councils generally require a Waste Management Plan to be submitted with a Development
Application, which applies to:
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Site preparation (green waste)
Demolition and destination of demolished materials
Construction waste and destination of waste material
Waste generated from occupancy (allow for compost heap or worm farm system)
Before starting to build
Make sure your builder has prepared a waste management plan that is communicated to
suppliers, subcontractors, labourers and staff. Ensure this is monitored and adhered to.
Ask him to plan the site to reduce waste at different stages (excavation, building structure,
envelope, interior fit out, finishing) and require subcontractors to adhere to the site waste
management plan.
The following table illustrates typical construction waste generated during a build.
Waste
Description
Soil
Concrete based
masonry
Brick and tiles
Timber
Vegetation
Metals
Plasterboard
Hard plastic
Paper
Others
Total construction
waste
Percentage of total
waste (by weight)
36
16
16
10
3
2
2
1
1
13
100
During construction
A considerable amount of waste material can be generated during construction, a large
percentage of which can be avoided if sustainable practices (eg prefabrication,
standardisation) are observed. It is in the builder’s interests, not to mention the
environment’s, to minimise waste requiring disposal.
Ordering and purchasing
Estimate quantities accurately, aim for nil waste allowances and avoid over-ordering.
Purchase materials and components that can be re-used or recycled. Plan to limit the
number of skips used in accord with your total waste budget.
Packaging
Negotiate with your suppliers to:
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minimise packaging in their deliveries
only use packaging that can be re-used or recycled
take back packaging once goods are unpacked
Site waste management
Include the waste management plan in site induction procedures and train labourers to
observe the plan. Monitor the site waste management during construction.
Reward good progress.
Provide labelled receptacles on site for waste in the following categories and volumes:
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timber recycling bin 3m3
mixed waste disposal bin 3m3
metals recycling bin 3m3
brick, tile and concrete recycling bin 3m3
During occupancy
This is more of a sustainable living issue, however waste management during occupancy will
be more manageable if systems are designed-in to facilitate waste separation for recycling.
Install under-bench systems in the kitchen to encourage recycling at the source and ask your
builder to allow for a compost system and worm farm in the garden are.
List of images:
Solar orientation - both from Tony
Insulation - need a generic picture of bulk insulation batts (preferably installed tightly a cross ceiling)
and a roll of reflective insulation to illustrate the difference between bulk and reflective insulation,
source from wherever you like
Sealing - picture of leaks comes from Your Home manual (http://www.yourhome.gov.au/passivedesign/sealing-your-home )
Heating – Star stick out picture comes from http://www.energyrating.gov.au/
Hot water heating - pictures come from the net, but they could come from anywhere. I suggest a
picture of a solar hot water heater and an instant hot water heater as those are the two kinds of hot
water heaters we are encouraging people to invest in.
Windows - convection current picture comes from :
https://www.eeb.ucla.edu/test/faculty/nezlin/PhysicalOceanography.htm .
I think we should have a picture of a convection current. Here is a link to a similar picture from
another educational website: http://www.propertiesofmatter.si.edu/Density_Creates.html
WERS logo comes from WERS website: http://www.wers.net/wers-home