Watts on?


A kill-a-watt meter.
Link goes to Amazon.

Everybody talks about “vampire loads” when discussing home electricity use, and I ran around with my trusty Kill A Watt [amzn] to see just what I had on.

Here’s watt’s on:

Item Watts kWh/Month kWh/Year Cost/Year @ $0.10
Garage Door Opener 3 2.19 26.28 $2.63
Radon Fan 20 14.6 175.2 $17.52
Upstairs Fridge* 30 21.9 262.8 $26.28
Downstairs Fridge* 20 14.6 175.2 $17.52
Computer** 40 29.2 350.4 $35.04
DSL Modem 4 2.92 35.04 $3.50
Main network switch 2 1.46 17.52 $1.75
Inkjet Printer 6 4.38 52.56 $5.26
Laserprinter 4 2.92 35.04 $3.50
Microwave 2 1.46 17.52 $1.75
Stove 1 0.73 8.76 $0.88
Wireless N 3 2.19 26.28 $2.63
Wireless G 4 2.92 35.04 $3.50
Wireless G (2) 2 1.46 17.52 $1.75
Answering Machine 3 2.19 26.28 $2.63
Cordless Phone Up 1 0.73 8.76 $0.88
Cordless Phone Down 2 1.46 17.52 $1.75
Furnace 4 2.92 35.04 $3.50
Sheevaplug 3 2.19 26.28 $2.63
squeezeradio x2 4 2.92 35.04 $3.50
squeezebox (on/sleep) 3 2.19 26.28 $2.63
Roomba 4 2.92 35.04 $3.50
Doorbell 2.5 1.83 21.9 $2.19
macmini/sleep 5 3.65 43.8 $4.38
LCD monitor/sleep 0 0 0 $0.00
mythbox/sleep/ups 8 5.84 70.08 $7.01
receiver standby 2 1.46 17.52 $1.75
network switch 2 3 2.19 26.28 $2.63
Envoy 1 0.73 8.76 $0.88
Total: 186.5 136.15 1633.74 $163.37
<10W Total: 76.5 55.85 670.14 $67.01
*avg** now only 18W!

Wow, so 186W of “always on” items in the house (where the fridge loads were averaged over time…)  And the thing is, I already went around trying to reduce these loads (for example making sure the Mac Mini sleeps, plugging the TV & subwoofer into the switched outlet on a receiver, etc).

Even excluding the “mandatory” things (refrigerators, radon fan, email/web server) it stil adds up to 670kWh/year.

And in total, 1600kWh per year … that’s about 3/4 ton of coal burned every year* for the sake of my roomba, laserjet, doorbell…  Nickeled and dimed in mostly 2W-3W-4W loads.  Ouch.  Surely I can live without some of these things?

*well, in theory I generate most from solar and buy wind power for the rest, but that only goes so far.

11 thoughts on “Watts on?

  1. Hadn’t done the annual math on our always on stuff — but it does add up, definitely.

    In terms of EV miles, 670 kWh could get you 2,680 miles at 4 miles/kWh ;-)

    Did Kill A Watt do the math on the above chart for you?

  2. Why is your Mac Mini so high?

    Interestingly my Koolu (AMD Geode box) is 6W, while my desktop (Shuttle box) off (not in sleep, just off) is 6W.

    Aren’t there powerstrips you can buy that mitigate/fix this problem?

    • @duffolonious – the mac mini is a few years old, but – it sleeps at 5W, I don’t consider that too high. Another option would be to set it to actually shut itself off, not sleep, every night – and it’d stay off until my kid turns it back on again. :)

      The thing about power strips is that they, well, turn things off. Believe it or not, almost the entire list above -is- in use throughout the day, or at least needs to be ready to be used. I’ve turned off or power-stripped the things which have obvious, planned use cycles.

  3. Thanks, Eric! I just got my first electricity bill of the winter here in Tucson and choked – it’s double what I paid in the worst month living in San Francisco. I just ordered the Kill A Watt and I’ll be doing some sleuthing.Is

  4. Great post! I found the breakout of the <10W especially interesting. Gives me pause to see it in black and white.

    Folks who live in Xcel Energy's service territory in Minnesota, Wisconsin, North Dakota, Colorado or New Mexico can check out a Kill-a-Watt ("Power Check") meter from a local library.

    More info at http://www.responsiblebynature.com/energy_smart/power_check

    With that version of the meter, you can download software that collects your data, graphs it and exports it to Excel or Word.

    Link to the software:

    We have a radon fan too, and your measurements of 20W and 175 kWh/yr made me cringe because I'm sure ours is comparable. Do you know if there is such a thing as a variable frequency (or adjustable speed) drive for radon fans? I doubt our fan really needs to be running all the time, which it is, but obviously I'm not a radon expert. Thoughts?

    • Hi Sheila –

      I made a point of finding an efficient radon fan, and we started with the lowest wattage then measured the levels… they were acceptable, so we stayed with the 20W fan. (I also had to make sure the installers didn’t let the exhaust pipe shade the solar panels ;) )

      I was probably the first person the installer ran into who was actually concerned about 20W vs 40W!

      I don’t know if variable speed would help; radon levels return to “normal” within a few hours of the fan turning off. If you wanted to invest the time and … energy, I’d see what your current levels are, see what the fan wattage is, and see if your installer would be willing to swap out a lower-wattage fan and re-measure…

      I think the other reason to use the lowest-wattage fan is that you run the risk of exhausting some conditioned air, and moreso with a larger fan…

  5. apologie for stalking you off the enphase site. but you seem to be knowledgeable, and willing to share information, traits seldom seen together (2%*2% i think) .. but I turn off the power to my house when I lock the deadbolt on the front door. How much do you think that actually saves in dollars… although I do it for sound reasons… the lack of EM while i sleep keeps me from having to wear that uncomfortable colander on my head and the tin foil codpiece.

    • Eh, the stalking makes me feel loved. ;)

      How much you save by flipping the big red switch would of course depend on how long you are gone, and how much power you would have used if you’d left it on!

      My guess? Not much. Electricity is too damned cheap!

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