Friday, June 09, 2006

Slowing the electricity leak - or how to save 10% or more on your electricity bill!

While doing some reading recently on how to become more energy efficient at home, I found information on how a lot of equipment is constantly leaking energy. Just like a leaky faucet - but without the annoying 'drip, drip, drip'...

For example, did you know that your computer probably uses power even while it's "off"? For an overview, see this article from PC Magazine.

Or that the clock on your microwave uses more power than the actual microwave feature? See this article for a good explanation.

Some of this power is used by the equipment for things like digital clocks, or the ability to receive an "ON" signal from a remote control. But some of it is just bad design, and just plain wasted - like the power used by a transformer that's not connected to anything. If you touch a transformer that's been plugged in for a while you'll notice that it feels warm - it must be drawing some power to generate heat!

For most electronics and appliances, it averages to around 4W of electricity each. It doesn't sound like much - until you start to add it up!

So, I recently conducted an experiment at home. Before I left for work one day I made sure that all of our equipment, lights, computers, central air conditioner, etc. was "off". Everything except for the refrigerator. Then I wrote down the numbers on our electricity meter. And when I came home I checked the meter again. Our house had used up 2.2 kWh while I was away. I was away for 9.5 hours, so over the course of a day this would add up to 5.6 kWh. Over a year, this represents 2028 kWh (or roughly 2 MWh).

Our refrigerator is rated at around 528 kWh per year, so this leaves 1.5 MWh per year of wasted electricity!

The next morning, I went around and unplugged everything that I could find in the house that I thought might be 'leaking':
computers and associated devices
portable telephone
TV, DVD/VCR and stereo

I unplugged everything except for the refrigerator, stove, and dehumidifier (which was turned off), and turned off the central air conditioner. Then I noted the electricity meter before I left, and again when I came home. What a difference! This time the house had only used 0.9 kWh over the 9.5 hours I was away. This represents 2.3 kWh per day, and 829 kWh per year. Over a year, this could represent a savings of 1198 kWh (1.2 MWh)! Last year our electricity bill was around 8500 kWh, so this represents a potential savings of 14% of our total electricity use! At today's prices in Ontario, this is about $115 savings per year. And electricity prices are only going to go up!

Of course, we'll only realize these savings if we keep this equipment unplugged all of the time. However, for most of the items 90% of the time they are not being used.

However, it is a pain to keep unplugging and re-plugging things. So we've purchased several power bars that have an Off switch. This allows us to, for example, turn on or off the TV, stereo and DVD/VCR, all at the same time. Of course, this means that we can't use our DVD/VCR as a clock any more. For us that's OK. It may be an issue if you use your VCR to record shows regularly.

[Edited to add:] I just thought of another advantage of unplugging your DVD/VCR and microwave - less clocks to update when you switch to daylight savings time and back again!

Now, if you multiply our savings by the number of households in Ontario (3,924,515 at the 1996 census), and you get 4704GWh (giga-Watt hours)per year! Convert back to Watts, and it's a draw of around 537 mW. Not enough to shut down Nanticoke, but still a significant amount.

And how much carbon would this save? Well, that gets a bit tricky, so I'll leave it to another post.

(If you're confused by all these measurements and calculations - like I was, see here for a good explanation.)

1 comment:

denuma said...

That's a really interesting experiment. I often wondered about all the green lighting that seems to be everywhere when you shut the lights off. Another aspect to consider is health. It has been shown (not sure where) that sleeping in a room that is partly lighted reduces one's immune system a bit. Best to sleep in a dark room - so turn of all those electronic pieces of equipment. LEDs