Monday, August 11, 2014

Vampire Electricity

There is a lot of discussion these days about vampire electricity--electricity that is used by an appliance or electronic device when it's not in use but plugged in. These can be things like the digital display on your coffee pot or your phone charger. Most of these discussions can be quite alarming when you see the statistics they list of how much electricity these objects use both in terms of your budget and the carbon footprint. However, the articles usually give one grand number without going into the specifics of individual devices. So recently when I discovered that Miss Landers had a Kill-a-Watt gadget that measures electricity usage of things that plug in, I had to try it. I used it with a few things around the house to get a feel of how much electricity they were actually using. I measured each object for 24 hours and here are the results.

Item KWH/24 hours
Toaster with display
Outlet only
Lamp-off, plugged in
Coffee pot with display
Computer Monitor

As you can see, the lamp (turned off), the toaster with a digital display, and the Kill-a-Watt device itself all consumed negligible amounts of electricity--0.02-0.03 KWH/24 hours. I'm assuming that that may be in the margin of error of measurement, but I don't know for sure. The coffee pot display only consumed a little more with 0.04 KWH/24 hours. (None of the above items were in use during the measurement. They were just plugged in.) However, the monitor and laptop did use noticeable amounts of electricity although a lot less than I thought they would. I didn't measure only when they were turned off, but all of their use during a 24 hour period. The monitor is in use quite a bit, but does go into a power saving mode at night. The laptop is from Ward's work and is quite large and old. I'm sure that many newer ones and certainly tablets use less electricity than this one. However, that's what we had. Even with their heavier usage, the monitor and laptop consumed less that 1 KWH in a 24 hour period.

I then translated this usage into what it meant financially and that was a lot harder than I thought it would be. I assumed that I would just be able to read the charge for a KWH off of my electric bill, but it's not so simple. Besides that number, you also have to add in the additional costs that you pay every month. I ended up with $0.12/KWH as a reasonable estimate (only about half of that number is actual electric use). Rates vary across the country, so you may be paying more or less for your electricity. What I saw was that even if I leave all of these objects plugged in for a year, they're not going to break the bank.

I had a lot more measurements planned, but Theo took the device back with him one weekend. He wanted to measure various things in his apartment trying to see if he can cut his budget any more--mostly if there is a more efficient way to cool things. When I get it back, next up will be the TV. It's an Energy Star one and is supposed to only cost $6.00/year to operate (plugged in all of the time, 5 hours/day on.) I'm interested in that one in particular because it is supposed to be one of the bad offenders of drawing phantom power but the $6/year doesn't suggest that. We'll see.

Until next time...

More general reading and tips on cutting back on your electricity use: