Does a dimmer switch use more or less electricty when dimmed ?

Answer 1

Modern dimmer switches have solid state switches in them that turn off the voltage for some fraction of a cycle. If the voltage is kept off half the time the lamp being dimmed is at about half brightness as a rough example. The dimmer does not consume a noticeable amount of power whether it is trying to keep the lamp's voltage off all the time, none of the time, or any fraction between those limits so the answer is NO CHANGE in dimmer switch when dimming.

However the lamp that is being dimmed uses less electricity when it is off more of the time - that is where there is a change..

Answer 2

Dimmer switches will use less electricity when dimmed. How do they work? Instead of diverting energy from the light bulb into a resistor, modern resistors rapidly shut the light circuit off and on to reduce the total amount of energy flowing through the circuit.

Here’s what your traditional light switch is doing right now: the switching cycle is built around the fluctuation of household alternating current, generally known as AC current. This type of current has a varying voltage polarity — in an undulating sine wave, it fluctuates from a positive voltage to a negative voltage. In other words, the moving charge that makes up AC current is constantly changing direction (60 times a second in the US!).

A modern light dimmer switch breaks up this wave by automatically shutting the circuit off every time the current reverses direction – that is, whenever there is zero voltage running through the circuit. This happens twice per cycle (that’s 120 times a second!). It turns the light circuit back on when the voltage climbs back up to a certain level.

If the dimmer is turned to a brighter setting, it will switch on very quickly after cutting off. The circuit is turned on for most of the cycle, so it supplies more energy per second to the light bulb. If the dimmer is set for lower light, it will wait until later in the cycle to turn back on, using less energy and saving your money.

To learn more, and to purchase a dimmer switch for your home, visit EnergyEarth.com -- blog linked below!

Answer 3

It uses less electricity. What a dimmer does is decreasing the voltage. When you dim a light, the brightness of the light diminishes and you would also notice that the color shifts to a warmer color (sometimes it's harder to notice because our eye quickly adjusts to the shift to make it look normal)

If the light is warmer, it means that the filament radiating light inside of the bulb is being heated to a lower temperature. To achieve a lower temperature you would need less electricity, not more.

I'm not sure this is the case for all bulbs and dimmers, but I know it's true for most household ones and also for the ones in lighting for film/video (which are the ones I have most experience with)

Answer 4

Less. The dimmer reduces the effective power to the bulb - less power=less electricity.