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Measuring energy usage

PostPosted: Mon Oct 04, 2010 1:17 pm
by CarbonetiX
Hey guys I was just wondering about what methods you were using to measure the energy efficiency of your building. Do you go to the trouble of physically measuring the usage of individual appliances or are you calculating it purely mathematically based on what it says on the box?

Re: Measuring energy usage

PostPosted: Mon Oct 04, 2010 1:32 pm
by Sou
I've gone around the house and measured everything possible. Some things I measured over several hours to a day (like the coffee machine, fridge, laptop etc). Others seem to draw fairly constant power, in which case I just measure for a few minutes and multiply by time on.

Got a few surprises - such as the heater for the fish tank. (The fish are now gradually getting used to a slightly lower temperature. Everyone has to do their bit. :mrgreen: ) Another more pleasant surprise was that the fridge doesn't draw as much power as I thought it would - nor as much as is indicated on the fridge label.

I'm just using a cheap $30 meter. I'm not worried about absolute accuracy. If something seemed off I'd check it against whatever it says it's rated at - but that hasn't happened yet.

Should have done this years ago!

Re: Measuring energy usage

PostPosted: Wed Oct 06, 2010 6:11 pm
by Cherokee Solar
Hi Carbonetix,

Have a look at all of the energy inputs for your house. Most of them are metered. When you are looking at energy it's not a bad idea to look at the whole of house energy. Good places are:
Electricity meters - Kilowatt hours per day average use
LPG or Natural gas meters - Litres or Cubic metres average use per day
Fuel useage for your vehicle/s - Litres per week
Firewood useage - Cubic metres per week
Then compare your useage with the average - which you may be able to find on your bill or with a bit of search on the Internet. It may surprise you.

I reckon our current building standards (and the star energy rating systems) are based around a mechanically heated and cooled house. They're a good guide but they don't take into account things like solar energy production, rainwater collection, sewage treatment etc...

PS: I used to have tropical fish too. My electricity bill halved to an average useage of 3Kw/h a day after it broke. It chewed up more power than my fridge! I'm on off grid solar now, so no more tropical fish!

Re: Measuring energy usage

PostPosted: Thu Oct 07, 2010 12:24 am
by bpratt
Cherokee Solar wrote:PS: I used to have tropical fish too. My electricity bill halved to an average useage of 3Kw/h a day after it broke. It chewed up more power than my fridge! I'm on off grid solar now, so no more tropical fish!


I had a 6foot tropical marine aquarium, and it was costing me around $200+ per quarter to keep it running.

Sold it last year to save money. :)