So I thought this was cool: the library has a device you can check out that allows you to see how much energy your household devices are drawing. For lightbulbs and such, it’s fairly obvious (a 60 watt bulb draws roughly 60 watts!), but I’ve ready about 
“vampire drain”: devices that drawn power even when they’re supposedly off. Your TV and printer may do this to stay “warmed up”, so that when you are ready to watch you don’t have to wait for the system to warm up or get ready. Your DVR or cable set-top box may be drawing power to keep a hard drive spinning.
Last week, I tried checking one of these Kill-A-Watt (ha ha) devices out and measured a few things around my house. I also did a quick calculation of how much each of these devices would cost if left on (or off but plugged in) for a month. Power in Seattle costs about 9.6 cents per killowatt-hour (i.e., drawing 1,000 watts for on hour).
| Watts | Cost / month | |
| iHome Clock Radio (no music) | 5.4 | $0.37 |
| Wahl Homecut beard trimmer | 18 | $1.24 |
| Humidifier (low) | 47 | $3.25 |
| HP Printer (off) | 5.2 | $0.36 |
| HP Printer (on, not printing) | 6.2 | $0.43 |
| Precor Treadmill (not moving) | 26 | $1.80 |
| Precor Treadmill (fast walk) | 120 | $8.29 |
| Macbook Pro, fully charged, on but doing nothing | 16 | $1.11 |
| Standup freezer (average over 48 hours) | 40 | $2.83 |
| 60 watt incandescent bulb | 60 | $4.15 |
| 11 watt LED bulb | 9.7 | $0.67 |
| Dell 20.5″ LCD Monitor (On) | 48 | $3.32 |
| Dell 20.5″ LCD Monitor (Standby) | 1.4 | $0.10 |
| Toaster oven | 1400 | $96.77 |
| Cable TV DVR | 40 | $2.76 |
| Space Heater | 1300 | $89.86 |
The Cable TV DVR is as reported here, since we don’t have one. Likewise, I wasn’t able to measure a TV, but would be curious to hear from someone who has one who can measure it on and off.
The device is free to check-out to any Seattle Public Library cardholder, and you can pick it up from the Wallingford branch.
(Photo by Tau Zero)
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Hi, wasn’t sure how else to contact you — the Library’s press releases have been bouncing back from the news submission email ([email protected]) since last week.
Thanks – this is really interesting and I am glad to know the library has such a device to check out. When you show the toaster oven costing $96.77 a month, is that if it is simply left plugged into an electrical outlet, or is that as if it was toasting something 24/7? Same question with the space heater. Those are huge dollar outlays for relatively small items. Illuminating!
For the toaster oven and the space heater, that’s if they were left on all month, not just plugged in.
Thanks for the clarification. Those numbers were startling, especially as those two items are sometimes used by people who may be trying to reduce heating and cooking costs or have limited options.
Sure, and of course they would save cooking costs – if your choice is between heating up a full size oven or a toaster oven to 350°F to warm up a sandwich. Though it might take a long time to pay for itself on that basis.
The effect on total energy cost is a little more ambiguous, here in a part of the world where most of the year we heat the house anyway. You’d want to think about how efficient the ovens are, at converting watts to BTUs and delivering the heat where it’s useful, how often does that overlap with central heating, whether the central heating is electric or something else, etc.
Very very interesting. Thank you so much. How about a microwave plugged in and only used once or twice a week for a few minutes? I am curious. I leave mine unplugged except when I use it.