Using a KillAWatt wattmeter, I noticed my brand new (Nov 2008) Sony HDTV KDL-46WL140 was drawing about 16 W when off, instead of 0.1W as specified by the Energy Star rating. Googling it revealed that the Electronic Program Guide keeps a significant amount of electronics turned on pretty much all the time, and it is not easily turned off.
The best resource about this subject was found on-line at http://www.deviceguru.com/hdtvs-dam-pops-energy-stars-bubble
I have downloaded the text here just in case the link would go away.
HDTV’s DAM pops Energy Star’s bubble
February 7th, 2009
DeviceGuru recently reported on a reader’s so-called “Energy Star compliant” Sony HDTV that consumed 150 times its advertised standby power spec. After communicating with both Sony and the EPA, the reader eventually managed to put his insomniatic TV to rest. Here’s how.
Martin Hellman writes…
I thought your readers would be interested in hearing how the Saga of my Sony TV’s power-sucking “sleep mode” ended. As you’ll remember, this is a Sony 37-inch LCD (model KDL37XBR6), bought last November and specified to draw less than 0.1 watts in sleep mode, whereas my power meter showed it drawing 20 watts 75 percent of the time it should be sleeping, for an average of 15 watts — 150 times the stated value.
DAMed if you do, DAMed if you don’t
When I last wrote to you, I suspected that the problem was with the TV guide feature. Some sleuthing had shown that the EPA exempts “Download Acquisition Mode” (DAM) from sleep mode and, based on my power measurements, I guessed that the TV was in DAM 75 percent of the time that the TV was “off.”
Worse, there was no documentation in the manual on how to turn off the TV guide so that I could determine whether this was the source of the problem. If it was, I’d leave the guide off since it wasn’t that important to me. After several back-and-forth emails with Sony and the EPA, I learned how to turn off the guide and have confirmed that it was the problem. Now, my power meter is happily reading 0 watts all the time the TV is off.
Disabling the DAM, step-by-step
If anyone else has a similar TV, here are the directions for turning off the guide:
Upon completion of the procedure, I turned off the TV. About 30 seconds after being turned off, I heard a “click” and the power went down to 0.0 W
A note of hope:
The EPA was not happy to learn that the DAM exception was consuming so much of the OFF time. They had understandably expected that such a small amount of data would not take long to download and told me they will be considering this problem in their next update to the Energy Star requirements.
For those who want to make similar measurements, the Kill-a-Watt P4400 is a low cost (currently $23 on Amazon) unit and Brand Electronics sells more capable — and expensive — power meters.
As noted in our prior coverage of this sort of problem, developers of next-generation, “smart,” consumer products seriously need to reconsider their power management strategies.