does turning electric lamps down on a dimmer reduce electricity consumption?

Question

we are in a quandery at home as we have dimmers on almost all our lights so 'low'energy' lamps will not work .... but i think just reducing the brilliance will reduce consumption...
thanks for reading this and maybe having the knowledge to answer...
Mike

Answer 1

As long as it is a solid state dimmer and not an old rheostat.
Also, you dont save as MUCH energy as the light is dim.
the compact flourescents save more money than dimmers, so maybe look into those.

Answer 2

Yes they do.

You have many answers out there, including one that says all the other are wrong, which is actually wrong itself.

household lamps are powered by alternating current. Dimmers contains a triac that is switched from a control circuit. The triac is switched on at some point in time (the delay depending on the dimmer setting and called firing time) after the voltage sinewave starts to rise and stays on until the mains wave returns back to zero. The power used being equal to the area underneath the waveform and therefore less as the dimmer is reduced and the "firing delay" time increased.

Yes there is some losses in the dimmer as heat but this is fairly small compared to the reduction in power to the light.

Answer 3

Almost all dimmers available today are solid state, using a technique called Pulse Wave Modulation.
These work by switching the supply on an off rapidly with a duty cycle proportional to the dimmer setting.
If you turn it down the power consumption is reduced (not directly proportional as there are losses in the system).
Using rheostats aren't particularly suitable because they convert unused electrical energy into heat. In a large room, your switch would get very hot if running at a dim level for a long time.

Don't use fluorescent bulbs with a dimmer as the waveform chopping will cause the bulb to operate in its most inefficient phase of operation.

PWM is also used in DC motor control for similar reasons, plus because when it is "on" you have full voltage available giving maximum torque.

Answer 4

Modern electronic Dimmers do save electricity when the lamp is turned down low. Power is a function of Voltage x Current for a resistive load such as a filament lamp. The electronic circuit inside a dimmer switch reduces the average voltage to the Lamp by only supplying part of each complete cycle or by switching on and off very fast fast to supply only a proportion of the cycles per second. In UK the frequency of AC is 50Hz in US it is 60Hz. Or 60 cycles per second. If we turn off 30 of those cycles per second the lamp will only receive 50% of the Voltage and so 50% of the power saving money.

Answer 5

Yes, but at the cost of reduced efficiency.

Whenever voltage (and current) are changed (reduced in this case), there are losses due mainly to heat. If you feel your dimmer switch, for example, it will likely feel warm to the touch. That is electrical energy lost as heat; that is electrical energy not going into the lighting of your room.

On the other hand, the amount of current drawn by dimmed lights is definitely less than if the lights were full glow. And you should see a reduction in kilowatt usage if you dim the lights (or use lower wattage bulbs) and all other electrical usage remains the same.

PS: One answerer suggested fluorescent bulbs...excellent idea. They now have great fluorescent bulbs that screw into incandescent bulb sockets. A fluorescent bulb (FB) will burn 14 watts of power, but produce the lumens (light) equivalent to a 60 watt incandescent bulb. Further FB are expected to last five times longer than the equivalent incandescent bulb.

There are drawbacks (aren't there always). FB's are generally not dimable. For a considerable extra price, you can get dimable FB's; you'll pay big bucks for each bulb. FB's are not instant on, like incandescent bulbs. There is a warm up time of about a minute before the FB's are glowing full lumens.

PS: One of your answerers wrote "They merely offer varying resistance resistance to voltage and not current," Clearly this answerer has overlooked E = IR and E/R = I. For a fixed voltage (E = 110 to 120 V) at the switch, when the resistance is increased, current has to go down. It's the current that causes a filament to glow due to expended power (wattage) = I^2 R as heat.

Answer 6

If you dim a light I presume that it does not use as much electric because of a lower power to light it!
It is all to do with current.
I forget the formulae from years ago but is something like volt times the amps equals wattage.
So if you turn down the amps you are using less wattage therefore the lamp is dimmer.

Answer 7

most of the answers including above are WRONG.
Reduced efficiency obviously does not reduce consumption and the person obvioulsy does not have a physics degree and is babbling incorrectly hoping to impress!

dimmer switches other than triac DO NOT reduce electricity consumption.
They merely offer varying resistance resistance to voltage and not current
Lower wattage bulbs will use less energy.
Energy saving bulbs also use less energy but there is question as to whether the increased cost of the bulb will outweigh the potential fuel saving.

Answer 8

If you use a dimmer switch it will reduce your electricity consumption from full to a quarter depending on the setting that you choose !
If you dont believe me ! watch the wheel in your meter when you turn down the power to your lighs with the dimmer switch !

Answer 9

I don't think it reduces consumption.

Answer 10

yes it lower,the circuit inside is using semiconducter component its name triac,its controling the voltage and current insame time.