I'm thinking about programming my lights to dim to 50% instead of running at 100% full on. Will reducing the % on from 100% to 50% save electricity or is the other 50% dissipated as heat thus absorbing the same amount of electricity?
Modern dimmers do save electric when dimmed, but nowhere near the dim level. Dimming to 50% will save perhaps 10% to, at most, 30% depending on the type of load and dimming efficiency of the dimmer with a particular load - the specifics of which are rarely released. But, it's a saving nonetheless!
Maybe someone has tested with a specific type of load and will report. Bear in mind that the results pertain to that specific setup only, but can often be generalized to similar situations.
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I measured the following using a Icon lamp module and a 75W incandescent bulb. The lamp module is very old ('05 vintage) - I have not tested anything recently.
You are interested in the far right column (real power) vs the Icon level setting (column 1). In this configuration, with the dimmer set to 50% you would be consuming 46W of real power vs the bulb rating of 75W.
Wow, (72-46)/46 equals a whopping 36% savings. I do have a concern that at 10% there is no real power, though.
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Good catch Stu - The UPM meter (forerunner of the Kill A Watt) wasn't reliable with "complex" power. As the LampLinc output power is decreased the power draw of the LampLinc itself would become significant. The combination of in phase (incandescent bulb) and out of phase (LampLinc) power consumption would confuse the UPM.
I've removed the last two rows of the table. The remaining entries track the V*A readings which I believe to be accurate.
Electricity usage....
Posted - 07/26/2012 : 8:12:24 PM
Will reducing the % on from 100% to 50% save electricity or is the other 50% dissipated as heat thus absorbing the same amount of electricity? 
