Tuesday, 15 October 2013

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How much power does the "average" household use each day?

While it's hard to pin down a figure (a five person household would use a lot more than a single person household) most estimates are around 18 to 20 kWh. The Australian Energy Regulator has a handy little online tool that provides a more meaningful average household usage for your 'localised zone' (you provide your postcode) and number of people living in your home. 

For a two person household in Melbourne's east here's the averages:

Just what is a kWh?

Thankfully one of us has a degree in physics and can explain this one!

A kWh is 'kilowatt hour' - which is a unit of energy (not power). 

Energy is power multiplied by time, so the 'kW' is the power and the 'h' is the time (in hours). So if you have a 1 kW appliance running for 1 hour, then you've used 1 kWh.
As a point of reference:
  • A typical electric kettle about 2 kW
  • A split system air conditioner is between 3 and 9 kW 
  • An electric oven around 1 kW

How does the typical household use their electricity?

About a third goes on heating and cooling - so good insulation and putting on a jumper when you get cold can make a huge difference. White goods have the next biggest impact - so think about what you need plugged in and running year round and buy the most efficient product you can afford, it will make a difference to each quarterly bill. Lighting while around 10 percent can easily be reduced by replacing old inefficient bulbs with compact fluorescents. Better yet replace them with LEDs - expensive just now, but prices are coming down and the range of options getting better every year.

What's our average electricity usage?

About 4.5kWh (per day) in winter; about one third the average use. Here's some of what we do to use less electricity:
  • We have gas hot water
  • Heating and cooling - our house is well insulated, so we use a lot less of both. Our heating is underfloor hydronic heating, so uses very little power. In terms of cooling we have invested in good quality outdoor blinds and inside we have thick curtains. Last summer we ran our air conditioner no more than half dozen days, and when we run it we have it set for 24 degrees.
  • We make an effort to turn off lights when we leave the room. All of our lighting is compact fluorescent, which use less electricity. We are investigating the use of LED lighting which would reduce this further. 
  • Other than the fridge we don't have any appliances on standby, even our wireless Internet is off at the mains when we're out.
  • We've bought the most efficient appliances we could afford - washing machine, fridge etc.
  • We try to run a full load in the dishwasher and washing machine - and we line dry the washing, no tumble dryer in this house.
  • And finally a confession we don't own any of the following: TV, microwave, stereo, toaster or hair dryer - which also has an impact.

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