Publisher Kylie Ahern decided to
go ‘off-grid’ while renovating her
tiny worker’s cottage in Sydney’s
inner-west suburb of Newtown.
“Like many Australians I want
to do more to reduce my impact on
the planet and save resources.
There’s no need to renovate to take
your house off-grid. It just happens
that I am doing both at once,”
she says.
And by off-grid she really does
mean off-grid: no mains power
or gas, no water or sewerage
connections. Electricity will come
from solar panels with battery
storage ($29,000) and hot water
from an air-source heat pump
($3500). Quality ceiling and wall
insulation ($3000) means no
air-conditioning or heating will be
required. Water will come from
the sky into a 5000L undergroundtank ($10,000, pictured); sewage
will be treated by an aerated
waste-water treatment system
($7500) later in the project. A
grey-water system ($1900) will
take care of f lushing the toilet and
watering the garden using dual
plumbing pipelines (an extra
$1000) – one potable pipe for
drinking, cooking, showers, hot
water; another non-potable pipe
for f lushing toilets, clothes
washing and garden.
Kylie expects to save $1500 a
year on electricity, gas and water
bills in addition to saving 90,000L
of dam water, 345kg of food from
landfill by composting and
97,000L of stormwater polluting
the harbour and ocean.
Kylie is being guided by
sustainability expert Michael
Mobbs, who has made his owninner-Sydney home self-sufficient.
“You can take your first step to
going off-grid by simply buying
efficient appliances when you
replace old ones, investing in a
rainwater tank or replacing your
hot-water system with an efficient
model,” he says.
Kylie blogs at kylieoffgrid.com.au.< This year the Tesla Powerwall battery will
come onto the market with the full weight of
Tesla’s marketing power and the promise of
reduced costs. A leader in the electric-car
market, Tesla sold an incredible $800 million
worth of the groundbreaking Powerwall in
a week – before the manufacturing facility
was even built.
Other forms of battery technology are in
development too. Graphene and nanofl ow
technology (the latter an Australian invention)
may even, in time, outdo lithium-ion batteries.
But solar is the tip of the iceberg if you want
to save on heating, cooling and hot-water costs.
Geothermal heat-pump technology has also
become more cost-eff ective for domestic use in
the past couple of years. The US Environmental
Protection Agency says geothermal heat-pumps
can deliver “the most energy effi cient,
environmentally clean and cost-eff ective
space conditioning system available”. Solar and
geothermal heat-pump systems work well
together; solar produces power for lighting andappliances, geothermal heat-pumps cover
heating and cooling.
Geothermal heat-pump technology manipulates
the temperature diff erence in the air above and
below ground and transfers heat to or from the
ground. Pipes are inserted in the ground vertically,
in a horizontal grid, or in concrete footings.
Temperature-controlled air is delivered via the
heat pump, through ducting, radiators or in-slab
elements. Air-source heat-pump systems work
on the diff erence in indoor and outdoor air
temperature, but are not quite as effi cient.
Another Jeff ord, son Richard, is at the
forefront of this technology through his
company, Highlands GeoExchange. “Geothermal
or geoexchange costs about 70-per-cent less to
run than natural gas,” he says. “And it is more
comfortable because of the lower-velocity airfl ow
in a ducted system.” Richard puts the cost of
installing both solar PV panels and geoexchange
space heating for an average home at $30,000-
$70,000, with savings on power paying off the
system in seven to 10 years. #‘Geothermal or geoexchange costs about 70-per-cent less to run
than natural gas.’ Richard Jefford, Highlands GeoExchangeMAKING THE SWITCHThe following partners are
supporting this exciting
initiative:GOLD SPONSORS:
PLATINUM SPONSORS:
64 / AUSTRALIAN HOUSE & GARDEN
H&G DESIGN