Energy and Dimmer Switches
Date: April 2002
Does a dimmer switch on a light actually save energy?
A dimmer switch allows you to control the amount of current flow to the
light bulb. To answer your question you can save energy if you did not
want to have your lights ON "full blast". However, you do not get
something for nothing. The energy you saved is as a result of the
decreased intensity of your lights.
Assuming that the dimmer is a "step-down" A. C. transformer, it should
reduce the power used. If it is a variable resistor then it would not reduce
the power used. I think most dimmers are the transformer type since the
resistor would generate a lot of heat due to Ohms Law heating E = i x V.
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Update: June 2012