How much power does that device use?
(photo by johnwilson1969)
Last week I was thinking of using my Thinkpad as a file server and I started wondering how much power it would use if I left it on all day. Laurence said he had device for measure power consumption called a Kill A Watt.
After getting one and measuring the Thinkpad in a variety of conditions, I started wondering what devices in my home were poorly behaved with their power consumption. I went around measuring all the devices I could find for a couple hours.
One of the biggest surprises is that my Comcast digital cable receiver/DVR uses a whopping 42 Watts even when it’s turned off. That’s more than 3 times what my Thinkpad uses when set to save power. Another surprise was my Sony shelf stereo (circa 1999) which uses 9 Watts when it’s turned off and is just showing the time. As a result, I’ve hooked these poorly behaving devices up to a power strip that gets turned off unless I’m at home.
It turns out my Thinkpad only consumes 14 Watts when set to save power and with the screen turned off. All of my results for a variety of devices and chargers are now here on this Power Consumption Page. Feel free to measure your own devices and add to the page. I also measured a number of phone chargers, and contrary to the warnings in the video below, I wasn’t able to find one that drew any power when left plugged in.
Posted: January 23rd, 2008 under power.
Comments: 6
Comments
Comment from pasha sadri
Time: January 23, 2008, 10:09 am
I was surprised to find that the typical microwave uses more power in its life time because of the little time display than the actual usage of the microwave! I bet many appliances fall into the same pattern.
On the topic of automatically shutting down appliances when you are not home: houses with security systems can tell if you are home or not (through motion and heat detectors). But why can’t this information be shared with the heating and other systems in the house so that they can adjust themselves?
Comment from Phil
Time: January 29, 2008, 6:10 pm
What about flat screen TV’s (both LCD and Plasma). I’ve heard that they are power hungry even when off..
Comment from edward
Time: January 29, 2008, 11:09 pm
I measured my Samsung LCD TV (42″) and it drew 0W/7VA when off.
Comment from Hendrik42
Time: March 8, 2008, 6:17 pm
While I do not know the Kill A Watt, most of those devices can only pick up current/power above a certain “size”. So while one charger left plugged it may not show anything, try hooking up two or three chargers at the same time to the KillAWatt and see if it can then pick up the power drawn.
Regards, Hendrik
Comment from edward
Time: March 8, 2008, 10:02 pm
Thanks for the tip Hendrik, I’ll give that a try tonight and post the results.
Comment from zack
Time: July 16, 2008, 8:29 pm
I think that the kill-o-watt is not quite the right thing for measuring low power as it is designed more for refrigerators etc, and does not have the sensitivity to measure low power consumption accurately. Does anyone know of something that is accurate for low power devices? ( I think all these little chargers and things with clocks that consume power when off really add up because they are on 24/7.)
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