Hi Movie Lovers;

My HT and the rest of my house is progressing nicely (at the speed of government). I bounce from one project to another, and today I'm curious about LED lighting. Actually I've been digging into this for a while.

I feel that the compact flourescent lighting should be shelved asap. It's a poor light, it works sluggishly in cold weather, they don't last as long as advertised, they can't be dimmed with standard dimmers, etc. Oh, and mercury isn't my favourite stuff, either. In Canada they've been flogged by Dr. David Suzuki, an environmentalist with a pretty good reputation, but I happen to feel he should be pushing in another direction altogether. Light Emitting Diodes.

So I'll ask about LED bulbs. I had hoped to find some screw-in or GU-10 LED 120VAC bulbs, install them and treat them like regular household incandescent bulbs. But I guess that isn't about to happen, right? Apparently most of the 120VAC LED bulbs that I've found are not dimmable, which did surprise me. Any explanation as to why?

Here's my goal: I want to stop pi**ing away money to my electricity supplier, because they really are donkeys in several different ways. I'd like to use LEDs because they don't waste energy producing heat (also a bonus for a well-sealed Home Theater). But I want them to be dimmable. I also believe that LEDs use one-tenth of the energy that incandescents do. True, each little bulb would likely be a bundle of diodes, but still, they don't draw nearly as much current per unit of light output. Hence, less electricity wasted. Plus they don't burn out for eons.

Based on that, I'll ask two questions (finally!):

1. Is there currently any screw-in household LED bulb, or GU-10 type LED bulb that gives off the equivalent light of, let's say, a 35 to 60 watt bulb, operates with a standard 120VAC supply and importantly, is dimmable?

2. If the answer is no, would it be do-able to isolate the lighting circuits in my HT (and other parts of my house), and feed them with, say, 12 or 24 volts DC and use this to power LEDs ? Obviously I'd use LED's rated at the correct voltage. And the power would come from a DC adapter or other industry-accepted supply, rated to output enough amps and volts to match the LEDs. The adapter would be powered by household 120VAC, and I suspect that the LEDs would be dimmable, would they not? I mean most of us who have tinkered with electronics have hooked up a LED and varied the light output with a rheostat. From what I recall, LEDs do dim quite successfully, at least when fed a DC voltage. I'm still confused as to why this doesn't work in the AC world, even though I know what a diode does.

So please critique my plan. Am I missing something crucial? Would a DC supply eat up more energy just being on, than I'd save by using LEDs? Are there safety concerns that I'm missing?

Go ahead and jump in, all you electronics people. Speak layman or technical, which ever you prefer (I'll get some ace at work to translate engineering-speak if neccessary).

Thanks, and let's revolutionize the world, one light bulb at a time. Starting with my basement.

Cheers, Tom.

LEDs take DC power so the "bulb" would need it's own power supply built in to convert the 120 AC to something usable. To do this they need the 120 AV constant power. So no external dimming. The dimming will need to take place inside the bulb or on an adjacent power supply. You can buy LED bulbs but they are very pricey and aren't dimable. Your other option is to just a bunch of free LEDs and install them in some fixture with a dimable power supply. So your second point is very doable. There are on the web suppliers that offer both the LEDs and power supplies to do what you are wanting them to do. Just pay attention to the length of your wiring with the DC current.

I have an LED 120v rope light that is dimmable.

Here is a link for screw in 120v LED bulbs, kind of pricey.

http://www.superbrightleds.com/edison.html

I've been looking into this myself recently, albeit for recessed cans. There are two major products on the market now for LED recessed cans that can be part of new construction or retrofitted into existing cans. Halo makes one for there 6" H7ICT housing that is dimmable and gives off the equivalent of 65 watts (draws 12 watts). They are pricey though at $130 per retrofit bulb plus trims ($11 - 15 each).

There is a company called Cree that has a similar product that will fit into many 6" cans (Model LR6) as well as some 4" cans (Model LR4). Also draws 12 watts but gives you the equivalent of 65 watts output. These come in two "strengths" at 2700 and 3700 kelvin. These are also dimmable down to 20% without flickering. Cost is more reasonable at around $90 - 95 each (trims built into the retrofit bulb). Cree has a nifty little calculator on their website where you can punch in a bunch of variables to see how long it will take for these things to pay for themselves in savings. In my case it was 3 years and one month. I will probably go this route for all my basement cans as well as changing out the other 6" cans in my entire house.

I'd put up a power generating windmill too if I knew my neighboors wouldn't object. I think I would get the stink eye though if I did :rolleyes:.

PS: I also have LED rope lighting that dimms without issue (Lutron RadioRA dimmers)

Lutron has hardware available to allow dimming of LEDs ... just an FYI.

One of the problems with LEDs is the color temperature. In kitchens, they tend to turn food green. On the other hand, there are also LED fixtures coming to market with multiple colors of LEDs in a single luminary to solve the color temperature problem.

One of the problems with LEDs is the color temperature. In kitchens, they tend to turn food green. On the other hand, there are also LED fixtures coming to market with multiple colors of LEDs in a single luminary to solve the color temperature problem.

The Cree model's that I spoke of actually have a red and yellow (or green, can't remember) LED in them that diffuse together to somehow give off a pure white light. The Led's are hidden up in the fixture. All you can see is white light, even inches from the fixture. The higher kelvin fixture is said to "bring out the red in tomatoes", i.e. much less color distortion.

Yes, I believe one of their luminaries is 3500K...not yet daylight color temp. Someday perhaps we'll get closer to 6500K.

Holy crap.

For the price of those LED bulbs, you could buy at minimum 3-4 CF bulbs or a dozen or so regular bulbs.

do a ebay search for ledbulb.bizz store he sells nothing but led bulbs and has many bulbs that you are looking for. I have bought from him and service is fast @ friendly :) and if you cant find it that way google it

Holy crap.

For the price of those LED bulbs, you could buy at minimum 3-4 CF bulbs or a dozen or so regular bulbs.

This is what stopped me from going with LED recessed lighting. Even at CT's electricity costs (among the highest in the country), I determined that I wouldn't have return on investment for 10+ years. And that's assuming the LEDs last as long as they say they will. My personal experience with fluorescent lights is that about 1/4 of these fail within a few weeks (keep your receipt) or at least don't last nearly as long as they say they should. If LEDs are the same way, I couldn't justify buying them. I also considered that fluorescent light bulbs don't really seem to be as bright as they say they are. For instance, I have two 13 watt bulbs that say the two combined have the equivalent of a 100W incandescent bulb, but I compare the lights versus a 60W incandescent, and those are about equivalent.

Well Everyone;

Lots to think about. Like anything else, LED bulbs would be cheaper if they were produced as lightbulbs in large numbers. I suspect that will happen eventually, but I'll have to wait I guess.

The whole concept of paying around $100 for a "lightbulb" makes me want to hurl, big time. I have 16 canned lights in my HT, and plan to add more once I get the bar layout figured.

So, all you electronics guys, why is a LED bulb not dimmable using any typical dimmer in a 120VAC circuit? I understand that the LED might wasting half of the energy supplied to it, as it is a diode. Or maybe what happens is the LED is on when the electrons are flowing in one direction, but off when the flow is opposite. We presumably just can't see flickering on and off because it happens at 60 Hz. So again, why wouldn't dimming the LED in an AC circuit work? All we're doing is dropping the applied voltage.

Thanks to all who replied to this thread. Keep the info coming if you feel like it. Cheers, Tom.