Home' Homes : Homes 2011 Contents 106 Scoop Publishing | WA’s Best Homes & Design 2011/12
Greywater recycling is on the increase. But there
are no state government rebates, and federal
government rebates have been discontinued.
The average household produces about 90kL
per year of greywater (from sinks and showers),
which can be reused in the garden and/or for
toilet flushing via one of two types of systems.
The greywater diversion device diverts it
without storage or treatment, using a
hand-activated switch or tap to divert it
to the garden for sub-surface irrigation.
The greywater treatment system collects
and treats it to a higher quality for reuse via
sub-surface irrigation (when not disinfected),
surface irrigation and possibly toilet
flushing, and cold-water laundry washing-
machine use (when disinfected).
Simple diversion systems can be purchased
for less than $150, while treatment systems
start at about $3000, plus installation costs.
About 10 per cent of electricity consumed in
Australian homes is attributed to appliances
in standby mode. You can turn them off one
by one. However, there’s a more sophisticated
way. Standyby power reduction systems allow
a master switch to turn off all non-essential
outlets when you leave the house for a short
time or an extended period, turning the house
to ‘holiday mode’. In new houses it’s a nominal
cost to install these, but for existing homes,
standby power reduction systems can be
extremely expensive and difficult to retrofit. So
if you’re building, give it some serious thought.
No space for a solar hot water system? A heat
pump may be the answer. It uses energy from
the surrounding ambient air and doesn’t need
direct sunlight. It transfers heat from the air
to water stored inside a hot water tank, saving
about 60 per cent on your hot water bill and
an average of 2.4 tonnes of greenhouse gas
emissions a year. Heat pumps cost about $3000
before rebates. A federal government rebate of
$600 applies (with some restrictions).
Thermal mass is a very simple way of using
heat from the sun to warm the home without
mechanics, but can only be achieved through
correct solar angles. One of the more popular
ways to achieve this is using concrete or stone
floors and/or walls that capture the heat from the
winter sun through north-facing windows. The
heat is slowly released during the day and night.
An innovative take on this use of thermal mass can
be done using an internal wall made of rainwater
tanks. In winter, the sun falls on the wall and the
water absorbs the heat, which is radiated to the
rooms behind it. In summer, the wall of water
remains cool and any residual heat in the house is
attracted to and absorbed by the cold wall.
Heat recovery ventilation systems are another
low-cost renewable energy innovation, heating
the home using the sun’s energy. They work on
the principle of directing solar-generated warm
air into the house via fan-assisted ductwork.
There are different ways this can be done, for
example, using the ceiling cavity to trap heat.
Air in the roof space of a house can reach high
temperatures even during winter and this heat
can be directed into the home via fans, which
can be reversed to suck warm air out of the house
during summer. The roof space air temperature
can be further increased by replacing a section of
roof sheeting with clear polycarbonate sheeting.
This can necessitate a higher level of ceiling
insulation to ensure the excessive heat does not
enter the house during summer.
As these ideas require significant house
modification, they are more easily incorporated
into a new building rather than a renovation.
Links Archive Homes 2010-11 Homes 2012 Navigation Previous Page Next Page