Living on 1.5 kW - what appliances can I have?
The ultimate goal is to become carbon neutral or even energy positive. It’s
expensive to buy a huge solar electric system: the cheapest way to become
carbon neutral is to eliminate any wasted energy. The website
www.energyrating.gov.au has lists of appliances, showing how much energy
they use.
A 1 kW home can have
Per year
- An efficient new fridge 405 kWh
- A new dishwasher used on economy, every second day 130 kWh
- A 4-5-star top-loader washing machine (half of the washes are cold) 170
kWh
- Ten 11-Watt compact fluorescent globes x 4 hours a day 161 kWh
- A medium LCD TV, on 4 hours a day 230 kWh
- Vacuum cleaner 1800w x 52 hours 94 kWh
- Laptop:18w, 4 hours a day, 200 days a year 22 kWh
- A 70w ceiling fan or standing fan, 4 hours every day in summer 26 kWh
- 200kWhs are left for a microwave, iron, electric fan on the gas heater,
electric pump for solar hot water, electric clocks, radios and music. 200kWh
- Total 1440kWh a year
As you can see, it’s very tight, but it is possible, especially for a single
person or couple, to live on 1kW of solar panels – 4 kilowatt hours a day -
and use no net electricity. This assumes you have gas or solar hot water and
gas heating.
A 1.5kW home can have more of everything
It may be possible to have air conditioning if you use it sparingly. Check
its consumption and multiply that by the number of hours you plan to use it.
Insulate well and consider roof fans and “cool roofing”.
Beware of…
Old appliances
– these can use a lot more electricity. A small old fridge can use 700kWh a
year, an inefficient dishwasher (used daily) 350kWh, a washing machine
700kWh a year…
One pensioner was given an electric heater which had been thrown out. She
accepted it gratefully, without questioning its electricity consumption.
When her household electricity usage reached 21kWh a day, she decided to
take action. She changed her light globes to compact fluorescents and
replaced the old heater with an efficient new one. Her electricity
consumption fell to 7kWh a day. Don’t give inefficient appliances to the
poor – send the appliances to the recycling depot.
Electric hot water instead of gas or solar
An electric-boosted solar hot water system produces more greenhouse gas
emissions than a simple gas hot water service (with no solar panels). Why?
Victoria’s dirty brown coal-powered electricity produces four times more
greenhouse emissions than natural gas, for the same heat output. The
electric booster alone produces more greenhouse gas than a whole gas hot
water service.
- Replacing an electric hot water service with gas-boosted solar can save 6
tonnes of greenhouse gas a year.
- If you have an electric hot water service running on cheap off-peak
electricity, the dollar cost may be quite low, but it is still creating
about 7.5 tonnes of greenhouse gas a year.
- Off-peak-rate electricity tariffs are gradually being phased out.
- If you already have gas hot water, changing to gas-boosted solar saves
half a tonne of CO2 a year.
- 1kW of solar electricity saves 1.9 tonnes of CO2 a year.
- A 1.5kw system, correctly installed, should save 2.9 tonnes of greenhouse
gas a year.
So, if you want to save greenhouse gas, the first priority is to get rid of
your electric hot water system. If you have gas hot water already, the first
priority is solar electricity.
Alternatively use 100% solar or wind GreenPower.
Halogen down lights – these are described as “low voltage” but they are not
low Wattage. One halogen light is generally 50W, as much as an old
incandescent globe. Twenty halogens use1000W (1kW – the output of a whole
1kW solar system). They emit so much heat that they add to air-conditioning
costs, and the hole in the insulation above them increases heating bills.
They cause house fires. The cheapest solution is to ask your electrician to
put a normal ceiling light in the room and don’t use the halogens
Or, the 50W globes can be exchanged for 20W IRC globes. These are halogen
globes coated with infra-red reflective coating to concentrate the heat back
onto the globe, making them more efficient. This will save 60% of the power
bill. There is less fire risk with IRC (coated) globes as they don’t emit as
much heat. LED lights are a good but more expensive alternative.
Front loader washing machines that heat water with electricity.
Front loader washing machines use less water than top loaders, but they heat
up their own water with electricity. This happens even if you have solar or
gas hot water systems (which create much less greenhouse gas than
electricity). Make sure the front loader has two inlet pipes, one for hot,
one for cold and attach the hot to your gas/solar hot water system.
Alternatively use the front loader on cold wash with a powder like Cold
Power.
and dishwashers. Dishwashers also heat up their own hot water. They give
alternate cold and hot rinses. If you have an electric hot water service,
make sure the intake pipe for the dishwasher is connected to cold water, or
all your rinses will be in hot water.
There is a belief that dishwashers use less electricity and create less
greenhouse gas than hand washing. This is true only if you have an electric
hot water service. If you have gas or solar you use less energy by hand
washing in a bowl of water.
Desk-top computers: a desk-top computer can use 70W of electricity. A laptop
uses 18W.
Wide screen TVs: Ultra big ones use a lot of power, especially plasma TVs.
Ducted air conditioning and heating – electrically-heated outdoor spa pools
– swimming pool pumps…Small bar fridges and drink coolers: these can be
wildly inefficient. Check the energy star labels when you have ducted
heating or cooling installed. People tend not to notice stars when the unit
is in the ceiling or under the floor. The supplier may give you a 1-star
unit. Ask if you can close down the ducts to rooms which are not in use
before buying.
Avoid bar fridges.
Stand-by power – some appliances still use a lot of electricity when they
are on stand-by and not even working. Switch off at the wall. Devices are
available to turn everything off at the wall at once. You can buy a small
plug-in energy monitor from hardware stores or the EnviroShop to measure the
energy used by appliances.
Air-conditioning uses a lot of power – a 550 Watt air conditioner in just
one room, used for 8 hours a day all summer would chew up 400kWh (depending
on the temperature selected). Ducted air-conditioning for a whole house uses
a lot more. A geo-exchange heat pump (under the ground) can bring in 3 to 5
times as much energy as it takes to run it but these are not cheap.
Tips for saving energy and greenhouse gas
- Kitchen: when using a boiler jug for one cup of tea, just cover the
element. Do not fill it up more than necessary. Boiler jugs and microwaves
are reasonably efficient – otherwise, use gas for cooking.
- Put a lid on cooking pots. Keep the flames below the pot, not licking up
the sides.
- Rinse cereal bowls in cold water to remove cereal before it hardens. The
bowls will dry in the drainer. Use the dishwasher every 2 or 3 days, not
every day.
- Bathroom: hang towels up to dry, don’t leave them scrunched up on the
floor.
They will not need washing as often.
- Showers were only introduced about 50 years ago. Before then, people
bathed weekly but usually just washed with a flannel each morning, then
washed the flannel. Daily showers feel great, but they aren’t essential for
hygiene.
- Laundry – wash in cold water as much as possible. Put grimy items in a
bucket of hot water to pre-soak, rather than filling up the whole machine
with hot water.
- Iron once a week not daily. Don’t heat up the iron just for one shirt.
- Lighting: A 100 watt incandescent globe (on all the time) uses 876 kWh a
year, more than half the output of a 1kW solar power system. Don’t forget to
change over all the incandescent lights, even outdoor lights.
- Insulate well, and stick weather stripping (from a hardware store) under
doors, around windows, anywhere a draft gets in.
- Curtains should touch the floor, to prevent warm air circulating up to the
glass in winter and getting cold.
- Use external blinds on the north and west-facing side of your house to
keep the heat out.
- Cool roofing paint will keep the house cool without turning on air
conditioning.
- Avoid electric heaters, cookers and hot water services unless they run on
100% GreenPower.
- If you care about global warming, beware of GreenPower based on hydro
power. This is renewable, but the hydro dams emit a lot of methane and
nitrous oxide, both potent greenhouse gases, from rotting vegetation. Choose
GreenPower that is based on solar, wind power or landfill gas, not hydro.
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