Light Switch Dimmers

Soldato
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So, I'm in the process of re-wiring my property and im deciding on whether to use dimmers or ordinary light switches. I just wanted to know: Do dimmers (that allow you to change the intensity of your lights in your home) help save on electricity?
 
Associate
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the variable resistor in the dimmer just dissipates any of the power that isn't used in the light bulb as heat and sound (the slight buzzing you hear from them)
 
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Can't be used with ceiling fans either. Well, thats not strictly true because Hunter Ceiling fans can and do work, but they are remote control and have internal dimmers.

Would like to say that they are the best you can get, we have them in every room! VERY quiet (providing they are mounted correctly) and complete with dimmer fuctions.

Check out their website, they are from the US, but there are dealers here.
 
Soldato
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Minto said:
the variable resistor in the dimmer just dissipates any of the power that isn't used in the light bulb as heat and sound (the slight buzzing you hear from them)

No, thats not how they work at all (well not these days, old theatre dimmers from days gone by did), if they worked like that then they'd get a lot hotter than they do, and be a lot bigger than they are

They work by phase cutting... switch on at the beginning of the the half cycle and bright light, switch on towards the end and dimmer, everything resets at the end of the half cycle to start again

Also, it should be noted that adding series resistance would reduce the power taken anyway, just not in a very efficient way becuase of the power that remains, some goes into the load and some into the series resistance


Anyway to answer the OPs question... yes they do save money (at least assuming a domestic meter that measures true power, rather than apparent power, whether they save money on a meter that measures apparent power is a question that its two late to thing about, though its irrelevant to this thread), but not as much as you imagine, if you dim the lights to 50% you are using about 75% of full power. If you are using many downlights, split them off into separate banks and switch them individually (oh, side point, derate dimmers by 50% when using with halogen lamps if thats what you are doing... the transisants are greater than with normal lamps :) )
 
Soldato
OP
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NW London
I was thinking about having 7 (halogen) spotlights in the lounge, in 3 banks, controlled by a triple light switch. So this would enable me to switch on only the lights that i want. This should enable me to save power.

It was just a thought about the dimmer lights. I read some adverts stating that dimmer switches allow savings to be made in electricity and ive always held the idea that this is not the case.

Of course if u really want to save money then energy saving light bulbs are the answer, though they dont look particularly nice.
 
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