The Kill-A-Watt electric usage meter
A while back I picked up a Kill-A-Watt electric usage meter, at the time the cheapest place was Ebay, but I am sure that many places have it the same or less now. I paid about $25 shipped. My electric bill in my small apartment was killer and I wanted to figure out where all the power was going.
I first got it in the winter when there was no A/C in use. So I went around the apartment unplugging things and plugging them into the meter. How much was my cheap clock radio from China using? The answer: not even enough for the meter to measure. A device must use at least 1 Watt for the meter to be able to register anything. Same story with the cell phone charger, laptop charger, etc. All the things that you read about in the newspaper as “phantom loads” really don’t use all that much power.
Now for the things that do use alot of power. Comcast cable box: uses ~30Watts regardless of whether it is ON or OFF. The only way to make it stop drawing 30 Watts is to unplug it(or turn it off with a power strip). The downside of actually doing this is it takes up 30 minutes to re-download the guide data and channel names after you plug it back in. So if you leave it plugged in all month its going to use 21.6 KWH. At $0.17 per KWH that I am currently paying that comes out to$3.67 a month/$44.04 a year! That’s almost as much as it costs to rent the box from Comcast. I’m glad I only have one cable box.
I like to leave my PC turned on all the time as I log into it remotely and like to have it available. Do so appears to be very expensive as it draws 115W of power at idle, it ramps up as high as 180W under full load (3D benchmark running). But for the most part its sitting there idle drawing 115W. That’s 82 KWH per month or $14 per month (ouch) or $169 per year (more ouch). In response to this I got my Wake-On-Lan functionality working and now turn it off whenever I go away but still have it available because I can power up remotely.
The other big consumer is the refrigerator with uses on average a little less than 1 KWH per day. I say on average because its naturally going to vary based on how many times it is opened. What’s really amazing about this is that it uses almost exactly the same electricity as the stupid Comcast box mentioned previously. A large appliance with a compressor, fans, and a self defrost uses the same total electricity per day as that stupid little box.
Other than the mentioned devices there were not big surprises. Light bulbs, whether regular or CFL, used exactly their rated amount. Same story with my wireless router and cable modem.
So overall, I’d say keeping the Comcast boxes and PC off when I went away a few times paid for the device. In the summer it was useful to see how keep the window shapes open or closed made a difference in A/C usage. It is definitely a recommended device for anyone hoping to save some money on their electric bill.
