Does using a light dimmer reduce the power consumption?

Answer 1

No it doesn't. The reason for this is that a light dimmer simply varies the surface area of a resistor over which electricity has to travel in order to reach the lightbulb.

The smaller the surface area of the resistor, the brighter the light because more of the electricity gets to the light to power it. As you turn the dimmer to lower the light, it increases the surface area over which the electricity has to travel therefore increasing the amount of power that gets 'lost' whilst travelling to the light fitting.

A resistor is basically a piece of material that doesn't conduct electricity properly.

I think there are newer designs of dimmers that work better and do claim to reduce the amount of electricity used but they are not quite yet commonplace.

For more information look at this website - it's quite handy!

http://home.howstuffworks.com/dimmer-switch1.htm

And I used to wonder if my Physics GCSE was ever going to come in useful!!!

Answer 2

Yes, using a modern dimmer will reduce power used by your lights by rapidly cycling them on and off, and save you some money, but unless you consider also increasing the effective light output of the bulb you are using at a lower wattage input (e.g., by replacing your incandescent bulbs with a CFL or LED), simply adding a dimmer and dropping the setting will simply leave you in the dark.

Answer 3

the amount of savings you get on power consumption using a light dimmer is negligible. if you really want to reduce power consumption then switch to an energy saving light bulb and start making real savings on your power consumption.

Answer 4

Yes it does. The only thing you have to be carefull is that not all light sources can be dimed. The new more efficient light bulbs (Compact fluorecent) have a power adapter that requiere the full power.

Hope this helps

In answer to the claim that they dont save power, the old variable resistor don't (they just transform the power into heat), the new ones are a constant on/off swith and they do save power.

Answer 5

Not really: the dimmer itself uses some power and wastes some in heat and noise - you can hear them buzzing! Use normally-switched low energy bulbs instead.

Answer 6

It uses a rheostat much like the volume control on a radio, the same amount of power is always going into it but the rheostat limits through a coil just how much makes it to the device.

I've never measured it myself but I'd say it uses the same regardless.

Answer 7

Not sure that it does, why not just change to low energy light bulbs they are so cheap to buy and only use 20% of electricity compared to a normal light bulb.

Answer 8

Of course. A dimmer switch is nothing but a variable resistor.
resistance increases,current decreases.
Power=Voltage(constant 240V)x current.

So larger resistance>>>>smaller current>>>less power.

Answer 9

Yes. But not as much as putting a lower power bulb in.

Answer 10

Clive
In a word..........no
All it does is hold back the flow of eleticity, rather like the coil you used as a kid at school to generate high and low ampage.
be privalidged Clive, you got a serious answer.