Does using a dimmer switch reduce electricity usage?

Answer 1

All a solid-state dimmer does is fire a triac at the correct point in the phase to control the power output. It does not dissipate the excess power like a variable resistor. The triac has about 3/4 of a volt drop across it. With a 120W light bulb this means that the dimmer will dissipate 3/4 of a watt at maximum power, which is negligible. So the dimmer will save energy in the long-run.

The dimmer circuit is actually a power regulator, albiet a choppy one. The lower the setting, the less time the lamp is turned on during each cycle. Thus, the overall power consumption is decreased.

How do I know this? I've built light dimmers. Ask me about the ramp voltage.

The truth is logical. Less light less energy!

Not as much as switching to compact fluorescent bulbs.

Do not use a dimmer on CFLs, as it can damage both the bulb and the dimmer.Another option is to switch to an LED lighting which is a solid state lighting. The advantage of this is that you save as much energy as using a CFL while still retaining the capability to dim the bulb thus giving you increased energy savings.

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The answers above are not completely accurate. Dimming a light DOES cause it to use less electricity. There are many dimming technologies. Some do "chop" the wave using triacs or SCRs. Others produce a normal sine wave output at lower amplitude, although these are used more often in theatrical and commercial dimming systems.

It is possible to dim a CFL lamp without damaging the lamp or the dimmer. The CFL lamps must be designed to be dimmable (many are now, check the specs). Similarly, not all LED lamps are dimmable--check the specs (most are dimmable but depends on the electronics).

Answer 2

Newer dimmers are based on the "triac" principle which will cut costs of running lamps. This is achieved by allowing electricity to cycle through the bulbs at less than 60 hz thus causing the bulb to use less energy. Some old dimmers were purely resistive dimmers thus, electricity not being used by the lamp was dissipated as heat by the dimmer. This style dimmer showed no electricity savings.

Answer 3

WebbyWunda's answer:

Well, sort of ... except that - without getting too technical - the dimmer switch itself doesn't use the electricity, it controls the amount of electricity that reaches the light bulb on its circuit. Dimmer set higher = brighter bulb = more electricity used; dimmer set lower = dimmer bulb = less electricity used.

Although the previous answer said only incandescent bulbs, there are actually some other types, for example those designed for use with halogen bulbs, or certain types of fluorescent bulbs.

Previous answer:

Yes, but only on a conventional incandescent bulb. The electricity heats the element and the element glows giving off energy in the form of heat. Less energy equals less heat. It is the same as having a one bar or two bar electric heater. The one bar obviously consumes less energy. All that the dimmer does is give you a variable switch. If you have alternative kinds of light bulbs or light systems with Transformers in the loop, then you would have to ask someone who knows your system.

Answer 4

No, less power is used, but the reduction in power is smaller than the reduction in light, because the lamps are less efficient when dimmed.

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A perfect switch uses no power, because when it is on the voltage across it is zero, while when it is off the current through it is zero.