Dimmers - do they save energy?

[ey143]

Am I right in thinking that actually using my dimmer light switch does not actually save energy when you dim the lights?

Also, if I was to replace my MR 16 halogen bulbs with LED version, will I be able to use my existing dimmer with it? I know I have a voltage transformer above each light but I'm not sure the details.

 

[flameport]

They save some energy, but not as much as might be indicated by the brightness of the lamp.
Half power is significantly less than hallf brightness.

Dimmers and 12V leds in theory could work together. In reality there will be problems.

 

[ericmark]

The lamp will clearly use less power.

With a 12 volt electronic transformer the whole idea is to control the voltage to very close limits so the bulb is as a very precise temperature to extend it's life so rather pointless using an electronic transformer then trying to dim.

You may find compatible electronic transformers and dimming switches which allow it to be done but if going to dim then don't use extra low voltage or quartz lamps.

Most electronic transformers use a switch mode method of control so have a minimum as well as maximum output so in the main can't use with LED and if you can dim then can't dim below minimum output.

The LED is a current device rather than voltage and to some extent you can vary the light output although not the colour of that light. But most lights are voltage controlled so some where there has to be some circuit to change from voltage to current. This may be a simple resistor or another complex switch mode device.

As a result to control a LED lamp rather than a simple LED you have to be able to control the driver inside that lamp. Some are designed that you can do that but in doing so they become much more expensive.

Best idea is to be able to select how many lights are switched on rather than control output of each lamp.

 

[333rocky333]

From the lutron website.

Q. How do dimmers save energy?
A.

When the light is off, no energy is being used. The longer the triac is off, the lower the light output, and the greater the energy savings



Q. If the lights are being turned on and off won't the lights seem to be flickering?
A.

No.

No matter how bright or how dim, the light level is constant and smooth. Compare dimming to movie projection. A movie is actually 35 individual frames per second projected so quickly that you never detect a break in the section.



Q. Doesn't turning the lights on and off so quickly decrease bulb life?
A.

No.

Switching the bulb does not decrease bulb life; heat decreases bulb life. By reducing heat, bulb life is increased.





Q. Do Lutron dimmers increase halogen lamp life?
A.

Yes.

Dimming increases incandescent lamp life, and halogen lamps are incandescent lamps. Lutron test data suggests that all halogen lamps will have an expected lamp life similar to that of other incandescent (non power factor corrected) lamps when dimmed, i.e. a halogen lamp dimmed 25% has a life extension of about four times that of a non-dimmed lamp.

Lutron is continuing to test its dimmers with various halogen lamps from many lamp manufacturers.

 

[DetlefSchmitz]

A movie is actually 35 individual frames per second projected so quickly that you never detect a break in the section.

Wow - have they really changed that? It used to be 24 fps when it was real film.

Always ready to learn.

 

[JohnW2]

The lamp will clearly use less power.

It will, but as flameport said, with a filament lamp/bulb, the power reduction will be proportionately far less than the reduction in light output. If one dimmed to the extent that the filament was not quite red hot, it would still be using appreciable power, but there would be no visible light at all.

Kind Regards, John

 

[JohnW2]

A movie is actually 35 individual frames per second projected so quickly that you never detect a break in the section.

Wow - have they really changed that? It used to be 24 fps when it was real film. ... Always ready to learn.

I wouldn't learn that one if I were you Although there are (and have been) lots of 'standard' frame rates around (many for specialised use), I've never heard of 35 fps being one of them! As you say, 24 fps (25 in some countries) has been the standard for 'movies' for decades, but I think we may soon be seeing a shift to 48 fps.

Kind Regards, John