Out here in California, electricity is nearing a premium, I remember several years ago when they de-regulated the power industry to provide competition and better service/rates for consumers. Well, that didn’t work…rates sky-rocketed and there were many brownouts. It turns out that the industry was no where near being ready for something like that. Power brokers jumped in with all of their offers and then the scam artists and it was a big mess. Now they have it all cleaned up, it’s all nice and stable again. However, electricity is still not cheap, not very expensive, but not cheap either.
Saving electricity is a tricky thing…if you are looking to know how much you can save. We all know to turn off the light when we leave a room, but what about all the other stuff we left plugged in? How can you calculate how much electricity you are saving by unplugging your cell phone charger during the day for instance? Well here is how you can find out.
Your electric bill measures your electric usage in kwh or KiloWatt Hours. A watt is a measurement of electricity and a Kilowatt is 100 watts. A Watt Hour is the measurement of electricity used during a time period, and thus a Kilowatt Hour is 100 watts used over that same time period. For instance:
A 60 watt light bulb used for 1 hour = 60 Watt Hours ( 0.6 Kwh)
Divide the 60 Watt Hours by 100 (to convert to Kilowatt Hours or Kwh). 60/100 = 0.6 Kwh
Not too bad, pretty easy right? Ok, so it isn’t that easy every time…but it doesn’t get much more complicated. Take that cell phone charger for instance…unplug it please, look at the bottom side where that label thing is. No where on it does it say Kwh. Instead there is a measurement of it’s “Input” or how much electricity it uses while it’s plugged in (and yes it IS using that amount of electricity even though your phone is not charging). See what it says as the input…it probably has something like 100-240V~50/60Hz, 0.15A
What the hell does that mean?
Ok, first off, forget the 50/60 HZ portion of it, that relates to it’s frequency and is not important for our calculation. Next, forget the part that says 240V, that’s for area’s outside of the United States. We need to focus on the 0.15A portion.
Ok, in the U.S. we have 120V (V = Volts) that comes out of the electric socket. The charger draws 0.15A (A = Amps). To measure the electricity it uses, just multiply the Volts times the Amps. So for our charger…
120V * 0.15A = 18 Watts. Now let’s assume you leave it plugged in all day, but only charge your phone at night for about 8 hours, leaving 16 hours left that the charger is plugged in without doing anything except sucking electricity.
18 Watts * 16 Hours = 288 Watt Hours or 2.88 Kwh being used per day that IS NOT being used to charge your phone!
Ok, so let’s put that in terms of money. I pay $0.14 per kwh in San Diego. For me, that costs 2.88 Kwh * $0.14 = $0.40 per day in electricity. or $147 per year of wasted electricity! Oh what would I do with that $147. So let’s review:
V*A = Watts
Watts * Hours used = Watt Hours
Watt Hours / 100 = Kwh (Kilowatt Hours)
Kwh * your energy rate (see your utility bill) = $$$$