Is more energy required to dim incandescent lights than to have them on at regular output?

Question

I was thinking of putting dimmers in my home office, but I heard dimming the lights with a dimmer consumes more energy than having the lights on at regular output. Is this true?

Answer 1

The lights consume less power when dimmed than when at regular output but they are less efficient at the dimmed level. At regular output an incandescent light might be 10 percent efficient. At reduced output that efficiency can drop all the way to 0 percent where the bulb can produce no light but still draw power. This condition is not an possible with most dimmers but rest assured, at lower settings the efficiency will be reduced.

Answer 2

You can't use compact fluorescents on a dimmer. But using a dimmer on regular incandescents will reduce power consumption. The dimmer only conducts electricity for part of the sine wave (when dimmed). This puts noise in the circuit too because the dimmer intermittently turns on and off really fast.

Answer 3

First of all, if you're so worried about energy efficiency..
WHY THE HECK ARE YOU USING INCANDESCENT BULBS?

Switch to fluorescent bulbs, or even the new LEDs if avaialble.
The light quality of fluorescent bulbs has gotten quite nice recently. They more than pay for themselves in energy savings.

You can't "dim" fluorescents, but if the fluorescent is too bright, use a lampshade that you can reposition for more or less light. A simple, cheap solution.