Kill a Watt Results

I got my Kill a Watt device today and results are pouring in. It plugs in to the wall and the display shows how many watts are being used while something is plugged in to it. It also tracks kilowatt-hours that have been used since it was plugged in which could help when measuring electricity use by a refrigerator whose compressor only comes on every now and then. I should also note that just plugged in to the wall the device itself reads 3 watts, so I have subtracted 3 watts from all the results I’m showing below.

The first thing I tested was my HDTV receiver, which came in at 15 watts. On or off, it is the same. Then I tested my other home entertainment electronics. The VCR (which I haven’t used in years) measured 2 watts, but the receiver and DVD player didn’t even register when they were off. The VCR is pretty old whereas the DVD and receiver are newer and I think newer devices are better about not being vampires. The Dish satellite receiver uses 25 watts while it is on and only drops down to 19 watts when it has been off for a few minutes.

I figure that Georgia Power charges about 10 cents per kilowatt hour. So something that is on for 24 hours a day for 365 days per year (8,760 hours) costs 87.6 cents per watt. A 100-watt light bulb would cost $87.60 to run all year long. So that HDTV receiver costs me $13.14 per year to run. If I make good use of my remote control surge protector, it can pay for itself in 3 years. That’s not a great payoff, but I’ll take it.

I measured a lamp I have that uses a 23-watt compact fluorescent bulb in it and it came out at 22 watts. The timer I have that lamp plugged in to has a motor that turns the clock, so I have always worried that the timer uses more electricity than the lamp would if I just left it running all the time. But the timer only uses 2 watts, so that is a good deal (plugged in 24 hours a day it uses as much electricity as the light does in 2 hours; not great).

I moved on to the computer. I leave my DSL modem and wi-fi network running all the time. I also leave my Tivoli Model Two speakers on all the time as my computer speakers, even when the computer is off. I also have a charging station that has its own surge protector inside and plugged in to that are chargers for my Palm, iPod, and cell phone. All of that stuff plugs in to a surge protector and when I measured the consumption with the computer turned off, I got 17 watts. That’s not all that bad, I don’t think. Turn the computer and a monitor on and it bumps up to 151 (so the computer and monitor together are 134), but when starting a program like iTunes with the hard drive going full blast and the processor blazing, it bumps up to 184. I have a second monitor I only turn on when I need a bigger desktop and it uses 22 watts. My primary monitor uses 29 watts, but it is a nicer monitor and goes to standby if I’m not there.

My laptop measures about 20 watts when plugged in with a full battery, though it briefly spiked to 37 when I started iTunes. That’s still way less than the desktop. Asleep, after a couple of minutes, it dropped down to 1 watt. That’s pretty minimal. Just the AC adapter without the laptop plugged in, but the green LED lit, it registers 0. Want to save a lot of energy? Don’t use a desktop computer: a desktop uses about 6 times as much energy.

I tested my coffee maker as I made a cup of coffee. Once you flip the switch to start brewing, it spikes up quickly to 610 watts. I knew anything with a heating element would use a lot of watts. It did cut off completely once it was done brewing, though the heater would probably kick in every now and then to keep the coffee in the pot hot. The good thing is even though it uses a lot of watts, it doesn’t use them for long, so the total kilowatt-hours for a cup of coffee is 0.20. That’s only 2 cents, which is a price I’m willing to pay for hot fresh-brewed coffee.

I’ll post more results in a couple of days as I test everything else around the house. After that I won’t really have any use for the Kill a Watt, so I will lend it out if you are interested.

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