Monday, May 17, 2010

At Home and at Work with a Kill-A-Watt





This is a Kill-A-Watt. This is a Kill-A-Watt in action.

It's a specialized device that measures instantaneous energy consumption. I used it at home to measure power consumption from a Verizon set-top box under three conditions: 1) the box "off" 2) the box tuning a channel 3) the box tuning a channel with a 40" LCD TV on. I was surprised that with the box nominally off, it was drawing around 28W of energy. While tuning a channel it fluctuated around 28.5W. Finally with the TV on, the power consumption jumped to around 128W total.


So I called Verizon technical support to find out if I could turn the set-top box off overnight. They recommended not doing that. Why? During the night they occasionally distribute software updates to the unit. If the unit is off during an update, it may not be able to get it later resulting in a support call. Now that's 28W per hour on a 24 x 7 basis. That amounts to 245 KW per year times two since I have two set-top boxes in my house. That amounts to over 6% of my home's energy consumption last year!


I repeated a similar experiment at work attempting to measure my PC's energy consumption under these conditions: 1) the PC "asleep" in the morning with the monitor powered off 2) the PC "asleep" but displaying the login screen 3) the PC and monitor in use. I came up with these numbers: 108W, 175W, 190W.


I was surprised by the results of these experiments. The Verizon policy and the Vanguard policy concerning not powering-off the device were the same. Vanguard's policy revolves around the need to distribute software to PCs. The TIP Green Team, of which I am a member, has been told that Tech Ops is looking into powering off PCs remotely when there are no software distributions scheduled. If only Verizon would do the same for me!