Energy Usage Real Numbers

Several years ago I reported that my average electricity usage in the non-summer months was a meager 4 KW-hr per day—not bad at all for a 2,500-square foot home. In the last couple years, my energy use has been higher: as much as 5-6 KW-hr/day.

What happened? Well, I acquired some kittens. While they rarely flip any light switches or turn on any energy-sucking electronic equipment, they do have a water fountain that runs 24 hours a day, although I don’t imagine that uses more than, oh, 20 watts. A bigger heavy-hitter was a dual-CPU high-powered HP workstation, replete with four fans and a relatively speedy graphics chip. I wondered how much energy this actually used so I purchased a Kill-A-Watt power-measuring device (~$20). The verdict: the computer uses up to 222 watts!

Below is a table of the measured energy consumption of other items in my home. After the computer, the TV and the stereo system are the next biggest energy hogs, although at roughly 80 watts each, they use less than a Thomas Edison-style 100-watt incandescent light bulb. (My compact refrigerator, shredder and printer actually use more while operating, but they are only on sparingly or intermittently.)

Item In Use (W) Stand-by (W) Hibernate or Plugged-in (W)
OfficeMax shredder 84.1 1.1 0
Yamaha P-70 electronic piano 7.5 7.0 2.8
Princeton VL1716 monitor 28.2 0
Samsung ML-2580 laser printer 100-500 (printing) 6.5 0.0
HP xw-6500 workstation 178-222 6.0 4.7 ;4.2 (plugged in)
Dell Mini 9 netbook 10 (fully charged); 20-29 (charging) 0 (fully charged); 20 (charging) 0 (fully charged); 20 (charging)
Thinkpad T60p laptop with iGo charger 37-44 1.0 0
Viewsonic VP930b monitor 38 0 0
Kyocera cell-phone charger 0 (charging complete) 0 (phone unplugged)
Light with 23W fluorescent light bulb 25 0
GE GMR04HASACS compact refrigerator* 96-118 0 0
Onkyo TX-DS484 receiver 59 without subwoofer; 68-79 with subwoofer 1.7 0
Philips DVDR3505 2.2 2.2 (can’t turn off entirely)
Philips 30PW850H TV 82 0 0

*EnergyGuide estimated usage = 345 kWh/year = .95 kWh/day

Unfortunately, I never did get around to measuring the power consumption of the kitty water fountain, and I have since resold the Kill-A-Watt device. But it looks like I can’t really blame my two furry housemates too much for the increased energy usage, too bad.

The power draw (in watts) of my Dell Mini 9 netbook while in use after it is fully charged, as measured by the Kill-A-Watt device.

Your Voice

  • Adam says:

    Between November-December, we averaged 15.4KW-Hr/day. Biggest energy drain remains the pool filter. Current-era laptops are as powerful and speedy as desktop computers from a few years ago. No doubt I could lower our energy usage down further by retiring the Mac Pro with a new Mac Book Pro (but it’s not going to happen until next year at the earliest).

    What about your gas usage? I expect that to be higher given the temperature difference between Fort Collins and the Bay Area.

    • Felix says:

      Hi Adam. Looking at my gas bill, my gas usage ranges from 5 Therms (July, August, September, October) to as much as 124 Therms (December, January, February). I’m not sure if that is good or not, but if I was motivated I could cut back more. Been using more gas recently than in previous years due to having guests/girlfriend over more often, and so I frequently have the thermostat set at 68-70 degrees instead of my usual 59-64.

      What is your gas usage?

  • Adam says:

    Averaged below 14 therms/month for the entire year, but we rarely ever turn on the heat in the house (this month will be the exception). I recall that you have a gas range in the kitchen? Ours is electric, so our gas usage is really just for the house and water.

    • Felix says:

      Wow, that is really good Adam! That’s amazing you have only had to turn on the heat one month of the year!

      Looks like my average gas usage for 2011 was 54 Therms/month. That’s almost 4X more than yours! I use gas for cooking but it can’t be much since the months I use gas for only cooking and the hot water heater is 5 Therms/month. Heat is definitely the heavy hitter that I could optimize more.

      I’m going to see what I can do to insulate the house a little more. I know at the very least I could seal the front door a bit better.

      An interesting challenge will be to see how much I can reduce my gas usage in 2012 without making the misses uncomfortable. 🙂

  • Adam says:

    Our house just has wall heaters, not central air. Don’t know if that changes things. We’ll probably be using the heater a little more this coming year, since we don’t always want to be freezing in our own house (we typically wear lots of clothes in the winter months).

    • Felix says:

      How do wall heaters work? My home has central air.

      “We typically wear lots of clothes in the winter months” — reminds me of my first year in the house, and I was really into conservation. I’d wear a fleece jacket, wool hat, and even gloves inside the house (thin ones so I could type). Wonder what my gas usage was like back then.

      Ultimately I got tired of feeling like I was camping in the house, though, so about the extent I go to now is wearing pants and socks. 😀

  • Adam says:

    Wall heaters has gas hookups but the heat isn’t circulated through the house through ducts like with central air. The heat just pumps out of the wall… eventually, it gets around the house (or the room that you’re in). There are two wall heaters in the house. One in the living room and the other in the hallway to the bedrooms.

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