led lights

[bill tackaberry]

I have new dimmable light to install. Old light had a dimmer switch. What is the diferance on the switch for led lights and how can I tell if the one I have is any good and and if I need to buy a new switch

[EricU]

most LED's will say if they are dimmable with any dimmer or not. I assume if your dimmer is any age at all, it is the old style, and that a new one will work better with a LED

[The Famous Grouse]

In theory there is no difference on the switch end. A dimmer switch should dim LED bulbs as long as the bulb itself is rated for dimmer use. And you have to read CAREFULLY because many are not. If it doesn't say it's for use with dimmers, then it isn't.

LED bulbs are just fantastic, BTW. Through a slow program of replacing all my home bulbs as the old style incan bulbs died, I have cut energy use on average by over 500 watts per hour by my estimate and I think this is conservative.

The only issue I still have with LEDs bulbs is that they do not work with older automation devices like timed on/of switches and dawn/dusk switches for outdoor lights.

Grouse

[Robert Adams]

The Famous Grouse said:

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In theory there is no difference on the switch end. A dimmer switch should dim LED bulbs as long as the bulb itself is rated for dimmer use. And you have to read CAREFULLY because many are not. If it doesn't say it's for use with dimmers, then it isn't.

LED bulbs are just fantastic, BTW. Through a slow program of replacing all my home bulbs as the old style incan bulbs died, I have cut energy use on average by over 500 watts per hour by my estimate and I think this is conservative.

The only issue I still have with LEDs bulbs is that they do not work with older automation devices like timed on/of switches and dawn/dusk switches for outdoor lights.

Grouse

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Your old timers and motion detector lights don't work with led because there is no neutral at the fixture. The old ones bleed a little current through the bulb to power the circuit for the item. With an led the bleed current isn't enough to work it's way through the power supply circuitry.
The same goes for some dimmers.

Also be aware that led dimmers require a neutral wire because of this. And even though they require it I have found some that still bleed current through the bulb to power it instead of using the provided neutral at the switch. This if bad enough will cause leds to slightly glow a after turning them off. They will eventually turn off but it takes a little longer.

I even had one for our kitchen that the dimmer was bleeding power to ground to power it's circuit. Cheap dimmer switch at lowes...

Also if you are wiring lighting you are now required to provide a neutral in the switch box because the newer dimmers require them.

Now there are some led dimmers that don't need a neutral and used as a last resort but I wonder if they may be bleeding power to ground to power the circuitry... If they were then those wouldn't work in houses without a ground ie mid 60s(or so) and earlier.

[joe1086]

LIL

Many of the bulb manufacturers have a dimmer compatibility page. Might be worth Googling if you know which lights you are getting.

As an aside, about two years ago we started to replace all of the lighting in our home's public areas (about 20 LEDs). The bad news is that nearly half have failed (either they would not come on or would flicker). Good news is the three manufacturer's (Feit, Sylvania and Cree) have all replaced them under warranty. First question they asked if the lights were on a dimmer and if it was on the approved list (I said yes, but not sure if on any approved list...they replaced it anyway).

Keep your receipts, the proofs of purchase (UPC codes) the warranty info and which room/fixture they are installed in.

[JosephP]

You DO need a special dimmer for LEDs. I can't remember what the difference is, but the lights will not work reliably with an old switch. And yes, the light also needs to be dimable.

[Robert Adams]

JosephP said:

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You DO need a special dimmer for LEDs. I can't remember what the difference is, but the lights will not work reliably with an old switch. And yes, the light also needs to be dimable.

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Yup that is correct. However there are a few led bulbs that will dim with an old style dimmer but it doesn't work well.

The led ones are PWM. They also work with all lights.

[Cooler]

I wrote to Lutron about the dimmers. They said that while tungsten bulbs can be dimmed to as little as 2% of the maximum, most LEDs cannot be dimmed beyond 35% of maximum. So my 60 watt equivalent LEDs which do dim, are 21 watts equivalent. The fixture is a 3 bulb fixture so it is like having a single 60 watt bulb running.

Also I could not find any information on the longevity of dimmed bulbs. I have a 15 watt incandescent bulb (red) dimmed to probably 5 or 7 watts and it has been running continuously for 17 years. So incandescent bulbs have a longer life if dimmed. I don't know if LEDs are longer or shorter lived when dimmed. I wrote to the bulb manufacturer (twice) but they never responded.

[Robert Adams]

Leds will last much longer when dimmed because they are running cooler. Many low priced bulb manufacturers actually overdrive their leds which will run them hotter and shorten the life.

However what typically goes bad is it the leds themselves but the power supply. Running it off of a PWM dimmer will reduce the load on the power supply and extended it's life.

I have a dimmer on the can lights in the kitchen and it will dim them very well in fact close to what incandescent bulbs can do. Course that dim has no use for me.

[Snipe Hunter]

I've been installing LED Recessed can lights in the house on dimmers. I'm using a PWM dimmer. The can's including the lamp are under $9.00. Love em. Eventually everything will switch over to LED. I don't like the CFLs at all.