Friday, October 17, 2008

When "green" isn't

I recently attended (and presented at) an open source conference. One of the presentations was fascinating, covering all kinds of automation devices for home lighting, security, and automation. The presentation is here:

http://2008.utosc.com/presentation/51/

He uses Control4 wall-mounted dimmers to control the lights throughout his house, and motion detectors dim the lights on (gently) when you walk into a room or down a hall. The part I found fascinating, however, is that if you try to use his system to save energy, there isn't too much to be saved, because each wall box dimmer consumes a few watts of power, even when off. With a house full of these, that could be over 100 watts of standby power, added to whatever the central controller requires (maybe a few hundred watts if it's a PC). This means that you're burning between 3 and 10 kWh every day just to run the automation systems. He specifically pointed this out during the presentation so we would not try to save energy by burning just as much energy.

Referring back to the system in my kitchen that I described in my first post, since I'm using older generation Watt Stoppers, only one of them is drawing power, and it provides the DC supply to the illumra room controller and the other relays. If all the Watt Stoppers were powered by 120VAC, there would be a lot more standby power being used. I think it's only 2 or 3 watts, so it would probably be a wash to swap it out for 120VAC powered illumra single-channel room controllers, as they draw about 1 watt each. If I had single switches rather than three in one spot, then the power savings of the single-channel illumra receivers would be more compelling, compared to watt stoppers and the 3-channel room controller. Maybe I'll try out a one-channel unit somewhere else in the house.

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