LED lighting

[sendero]

When I moved to this house 3 years ago I installed CFL light bulbs in almost every fixture. CFLs are OK, if you get the right ones they put out a nice light and clearly use a lot less power and throw off a lot less heat than incandescents.

However, I've had a pretty good failure rate with these things. And they are toxic, so you cannot (or shouldn't at least) toss them in the trash.

The wife picked up a couple LED bulbs at the local home-improvement store on our last visit. I was skeptical, but decided to try one out.

I was impressed. This "60W equivalent" puts out as much light as my 100W equivalent CFL. (I can tell because I have two fixtures on my ceiling, one with each). This got me excited about the prospect of changing out most of our lights to LED.

But man, once I started looking into it I realized that using LED lights is a lot more complicated than I imagined.

I'm sure some of you already know all of this but for those who don't here goes:

1) Color - Like CFLs, LEDs have a "color". This color ranges roughly from almost bluish (almost useless in a home setting IMHO) to a warm yellow. The color is expressed in a number like 3000K or 5000K, which is actually a specification for the wavelength of the light. I like 3000K, a soft yellowish light that is very close to incandescent. Your mileage may vary but be sure you know what you are buying.

2) Dimmable - most LED lights, like CFL, will not work properly on a dimmer. You can get one that will but it will cost you more. I only need dimmers on about 1/3 of the lights in my house so I'm going to buy dimmable bulbs for those fixtures only.

3) Wattage equivalent - there is apparently no standard (as there seems to be on CFL bulbs, at least a de facto one) as to how many watts of LED light equal how many incandescent watts. I see bulbs called "60W equivalent" that use from 8 to 13 watts! I suppose the wattage does not tell the whole story so best to look at lumens, the actual light output of the bulb. Clearly it is better to have a bulb that uses 10 watts and produces 800 lumens than to have one that uses 13 watts and produces 800 lumens. You have to pay attention to all of these numbers!

4) Heat - LED bulbs are supposed to last a long time but many suffer from early failure. Some of these failures are probably related to poor/new/unseasoned designs but some are almost certainly related to heat. You are NOT SUPPOSED TO USE A LED BULB IN AN ENCLOSED FIXTURE! This present a problem for me because all of my ceiling fixtures are enclosed. If you install a LED bulb into an enclosed fixture IT WILL RUN HOT and IT WILL NOT LIVE A NORMAL LIFESPAN.


LEDs themselves (the actual semiconductor diode) are pretty cheap. What you are paying for in the (still a bit high) price of an LED bulb is the electronics required to convert 120 volts AC into a low DC voltage. Since this part (the power supply) is also a semiconductor device (at least most of it) the price will go down as volume is ramped up. I do not expect LED lights to ever be as cheap as CFLs or incandescents, but I think the price will halve or so over the next few years as more and more folks start using them. Please buy some and help get the volume up and cost down!

[intaglio]

1. There are Watts to lumens calculators

for example http://www.rapidtables.com/calc/light/watt-to-lumen-calculator.htm

Tungsten bulbs produce 12 - 18 lumens per Watt depending on age so a 100W tungsten produces 1500 lumens, a 60W tungsten is 900 lm and a 40W is 600 lm.

Metal Halide aka quartz halogen produce 75 - 100 lm/W again dependent on age though for most of their life it is about 85 lm/W

Both fluorescent and LEDs produce an average of 60 lm/W but newer LEDs can average much higher about 80 lm/W

Now from this it looks like metal halide is the way to go except they also have a much shorter life than LEDs and fluorescents and during the 10 years we used them we had 3 explode - one nearly causing a fire.

[sendero]

2. Yes...

... that would make sense. But I don't know why there is such a wide range of watts being marketed as "60W equivalent".

The bulb I've been playing with (and like a lot) says 12.5 watts, but my Kill-A-Watt says it uses 10 watts.

It says my 40W equiv CLF uses 12 watts and that my 100W equiv CFL uses 21 watts.

[intaglio]

3. Because the CLF requires a "starter", a very high voltage to set up the arc

One reason not to use CFLs if you switch them constantly on and off. Not only that but the electronic ballast is pretty complex and can go wrong. The "ballast" in LEDs is much simpler, basically a Wheatstone bridge.

[ConcernedCanuk]

5. CFLs are not suitable for certain uses.

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.
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Used properly, mine last between 5 - 7 years.

I learned the hard way, but found out the reasoning.

CFLs are most suitable for lights that are left on for extended times.

For instance, a closet or pantry light that is only turned on for a few minutes can kill a CFL in months.

Not only that, their is little or no gain economically (hydro usage) in 5 or so minutes as the ballast is still warming up.

Bedroom lights, that are usually on for only half an hour or so also fail earlier than lights left on for extended periods.

I use regular incandescents for the bedrooms and closets, but cfls for side table for reading lights at night as they are usually on for hours.

I use CFLs in my "trouble" light, some call it a drop light - maybe because us mechanics drop them a lot?

Anyhow, the 2 reasons I do this is of course the savings, but an unexpected bonus is the fact they do not heat up much. Even a 50W incandescent can give a nasty burn off the metal cover, and can scorch car carpets and melt vinyl upholstery. CFLs I can lay on the carpet for underdash work and it is never a concern.

Worked one place where my supervisor kept shutting off my trouble light (without saying anything) everytime he walked by it - bulb lasted 5 weeks - SO - replaced the bulb, switched the light on, cut the button, and taped it permanently on. I never unplug the light during the time I expect to be doing whatever I'm doing - 4 years later, bulb is still working.

CC

ps: have LEDs on order - let you know how that works out - I read my own hydro meter daily - yep; EVERY day, so I'll know exactly any difference in consumption.

[intaglio]

6. I've used LEDs for about 4 years now

Replacement GU10s for the lights in my lounge. They draw about 31W against 90W for the halogens. The first 2 I bought were really nasty and the ballast failed after about a month causing flickering. But since then plenty of use and no replacements.

[Curmudgeoness]

4. Why is everything so complicated anymore?

Life used to be so easy. You had light bulbs. You had television sets. You had a mop. I can't even navigate stores these days.

I believe that you are right, the prices will be at least half of what they are today in a few years. I remember the first CFL bulb I bought to try out was over $14, and that was in the 1980's.

I am using different bulbs in different situations here. I am still using some incandescent bulbs in places like the bathroom where the light is mostly turned on and off within a few minutes, since the CFLs are not efficient at that time frame anyways. I also use them in the dining room where I have a crystal globe and want to have clear bulbs, which I can't find in any other type of bulb...and this light is on a dimmer switch. I use CFLs in the closed fixtures that I have as well as my lamps that are on all evening. I have halogens in my bedroom fixture, just because I wanted to try them out and I like the brightness of the light from them.

[intaglio]

7. Because incandescents are seriously inefficient

LEDs produce nearly 3 times the light (lumens) for the same number of Watts. Over here in the UK and Europe even 60W incandescents are no longer produced or fitted to new built housing though it is still allowed to import them. The old style lights also fail more often and, burning hotter, are more likely to start fires.

Dimmable LEDs are also available at a fairly low mark-up.

[Kennah]

10. CFLs have come way down in price

Less than $2 each at Costco

[Curmudgeoness]

11. Yes, I know.

I have several CFLs, although they are not the only bulbs that I use. As I said, there are places where I do not believe that they are any more efficient than incandescent bulbs, like the bathroom, where I rarely have the light on the required 15 minutes for efficiency. Besides, CFLs give off a light that is not flattering, and since the bathroom is about the only place where I actually look in the mirror, I want to avoid looking worse than I already do.

[Kennah]

12. I figure I'll get all the natural light I can when we're living in our minivan

Even though it's sad commentary, there is a frugality to it.

[Curmudgeoness]

13. There is frugal, and then

there is frugal. I have been close enough to this scenario to hope I never see the day.

But at least there ain't much of a mirror to worry about.

[greeneyes646]

8. LED Lighting is the future

Yes, you are right ! Many people feel resistant towards switching to LED lights. But once they do so, they find it amazing. You should inspire others too !

[gopiscrap]

9. Welcome to DU

[Aquavit]

14. The other thing to consider with LEDs or any other light source

is the Color Rendering Index (CRI). This is a measure of how true colors are when seen under a given light source. LED light engines are far superior to CFL sources, and they're catching up on incandescent lighting as well. More info at Wikipedia: [link] http://en.wikipedia.org/wiki/Color_rendering_index [/link]

[sendero]

15. Addendum..

.... I have finished fitting my house (well, 95% of it, some locations such as inside the oven are not suitable for LEDs with LED bulbs. I want to make one correction to my OP.

SOME LED lights should not be operated in an enclosed fixture. I have found that the particular 40W equivalent bulbs (6 watts) I used do not generate much heat and can be safely used in any fixture.

I have also found that SOME 60W bulbs also throw off little heat. It's kind of startling how much variation there is here. I have one 60W bulb that runs really hot, but the Cree bulbs I wound up using really don't generate much heat and throw off a lot of light.

Thanks to everyone that contributed to this thread. My intention was to share what I have learned and not to scare anyone away from trying out LED bulbs. It's really perhaps not as complicated as I made it sound in my initial thread.

Distilled :

1) you will probably want 2700K (much like incandescent, almost yellow) or 3000K ( somewhat whiter) bulbs. Most of the time that is what you are going to find at your big box or mail order store.

2) Do pay attention to the wattage and lumens rating of the bulb, it varies a lot between brand. Fewer watts per lumen = good

3) I was able to replace most of my bulbs with 40W equivalents. These will run in an enclosed fixture no problem. Read the box - if it says "not for use in enclosed fixtures" heed the warning. Also to be extra-safe run one a few minutes and touch it. If it is too hot to touch (anywhere on bulb) then you probably don't want to use it in an enclosed fixture.

Thanks again!!!