OT: CFL Bulbs

[krw]

Yes and no. Since the LED is more efficient, more of the power will go into light (thus less into heat). The light is eventually turned into heat, so yes, in the long run, the heat output is the same but less heat will be dissipated in the fixture.

Yes, the LED would be "60 watt equivalent", or some such. It'll also state the actual wattage but it will be significantly less. Depending on the particular LED, this can vary a lot.

The problem is that LEDs are semiconductor devices so can't tolerate much heat. Every 10C rise in heat will probably reduce its life by

2.5x (or perhaps even more).

[Ed Pawlowski]

Yes, we got used to using watts, but lumen is what we really need to know so you can compare any type of bulb. It will take most of a generation to get used to that.

[whit3rd]

Alas, that's not literally true; no LED is 50% efficient, because the light can come out of the chip, or go the other way (and get absorbed). Fluorescent tubes could conceivably win the efficiency battle some day (because they don't have to include opaque parts).

[Bill]

I didn't know that! I knew about lumens and watts (and it bugs me when I see different lumens on bulbs of the same wattage--the traditional gold standard in brightness measurement! ; ) )

[Puckdropper]

krw wrote in news: [e-mail]:

Many of the LED bulbs have fins on them. They're heat sinks trying to keep the bulb and its integrated power supply cool. I haven't played too much with the small high-powered LEDs, but I'm sure they generate a good amount of heat.

Puckdropper

[Puckdropper]

Martin Eastburn wrote in news:Ifjhy.94831$ [e-mail]:

CFLs are great for where the light is turned on and left on. (Btw, there are instant on CFLs that are much brighter at start up.) If the light is turned on and off like a bathroom, there's only a small benefit to using them. If the light is turned on for only a minute or so, like a closet, they're no good at all.

Puckdropper

[G. Ross]

I have LED flashlights that get uncomfortably warm.

[G. Ross]

Just an old Codger checking in. My wife changed us over to CFLs when the craze started. I haven't noticed any decrease in the frequency I have to get out the step ladder and change burned out bulbs. No savings in buying the things. My electric bill has not decreased. Have not noticed that the summers are any cooler. Can't see any better. With LED's I think I'll sit it out a while.

[krw]

Different bulbs of the same wattage will have different output. Efficiency isn't a constant, even for one bulb technology. In a general sense, a lower efficiency bulb (lower lumens per watt) will last longer. It has a longer, heavier filament.

Don't forget color temperature, either. ;-) A "colder" (higher color temperature) fluorescent will look brighter than a "warmer" color.

[krw]

Right. I know people who use cut up beer cans to increase the size of the heat sinks, as well. however, if these are put in an enclosed fixture, the fins can't do their job and the bulb will overheat. The bulbs are, in general, designed to replace incandescent bulbs of the same "equivalent wattage". Using a higher "equivalent wattage" bulb though still lower actual wattage bulb than the fixture is designed for, may reduce the life of the bulb significantly. If you're doing this for economics, you may have just shot your wallet in the proverbial foot.

[krw]

Not true. LEDs don't absorb 50% of their generated light. In fact the direction of the beam is quite small. Diffusers are used (which do absorb some light) to make the light more omnidirectional. It's no problem to get LEDs that are twice as efficient (measured as getting twice the lumens per watt) as a fluorescent.

[krw]

Put a 15W incandescent bulb in your hand and it will get "uncomfortably warm", too. ;-)

[krw]

Other than our kitchen and basement, that's how all the lights in our house are used. The Kitchen now has LED cans (recently upgraded from fluorescent tubes) and the basement has CFLs, that will soon be replaced with 4' tubes. The rest of the house is incandescent.

[Leon]

I find CFL longevity slightly longer than incandescent. I don't think you will ever notice much of a difference in your electric bill month to month switching from incandescent as 15, 100 watt incandescent bulbs use the same energy as a small space heater which for me, 8 hours a day in my garage, does not make a blip on my energy usage either. The vast majority of your electric bill is to pay for Air conditioning, electric furnace, electric water heaters, and electric ranges.

One big advantage to LED's is that they do run cooler. This is great for under counter lighting where hot lighting can toast the wood. We keep our "ribbon" LED under counter lighting in the kitchen on 24/7 and neither the lights or cabinets seem to ever be even slightly warm. On all the time is great for getting up in the middle of the night for a cold drink of water.

[Leon]

You probably are not going to find a 60 watt LED, it would probably be brighter than the sun. LED's marked 60 watt equivalent are just that, equivalent. A 12-14 watt LED is equivalent in brightness to a 60-70 watt incandescent. And FWIW a 15 watt LED bulb hardly feels warm even when left on 24/7. The same said about a 15 watt incandescent will burn you if you touch it.

[Jack]

LED are far better than the CFL's other than cost, and the prices are dropping fast. Your electric bill probably won't change much, if at all if you have many large electric appliances. We have an electric stove,

2 large refrigerators and a large freezer. My work shop has a slew of electric motors and so on. Lighting, even incandescent, is likely a small proportion of the bill.

LED's are said to last very long time, so it is a good idea to at least put them where they are hard to change (after a burn out) I mostly replaced with LED's where the light is on for long times, where it's tough to replace (outside lamps with housings, shower lights with covers) and so on.

Unlike CFL's the brightness equals or exceeds the equivalent incandescent, which is a pleasant surprise. One caveat though, the HD salesman talked my wife into getting white daylights for the porch light and it really, really sucks. It is cold hard blue white light, that I hate. The warm softer lights are great, and look exactly like incandescent counter parts. I have 75w incandescent right next to 60w equivalent (11w) LED's over my pool table and you can't tell them apart.

[Brewster]

Yes! (I build custom LED lights/fixtures).

LEDs are very sensitive to heat and much is done to draw the heat away from the LED. The bigger problem is the LED driver (power supply) They suffer from the same issues that plague CFLs, usually the large electrolytic capacitor is the first to go due to heat. Ideally, LED lights (thinking recessed ceiling lights here) would have the power supply remotely mounted and low voltage distributed to the lights in a string.

In my mind, the big "thing" LEDs offer is better fixtures. You can fit an LED into a very low profile fixture (good by can fixtures). Under cabinet lighting will be (is) a big winner.

-BR

[Ed Pawlowski]

Why not invest less than $5 and try one? If you get the daylight version you may see better. Put it in the hardest spot to change and you may see you are not changing it as often.

I've been changing over and have yet to replace one.

[Unquestionably Confused]

Been struggling with SWMBO over the changeover. We both hated the CFLs (and why not they suck).

Think it was here that somebody clued the group into the LED style "shop lights" that Costco had on their shelves.

As I was about to bite the bullet and either replace 8 tubes in the garage or switch to new fixtures entirely - to avoid the warm up and flicker of the non-magnetic ballasts - I decided to buy four of the fixtures.

So far, it's the best thing I could have done out there. Even with the temperature at ~ 23 degrees, I flip the switch and the place lights up like a football stadium. These are warmer, I think, than the cool white fluorescent tubes they replaced but they are great.

Starting to see better prices and better selection of the LED's at the Big Boxes and so I'll start sneaking some in where I am the main user. SWMBO has a good point in that we had stockpiled a quantity of incandescent bulb, indoor/outdoor floods, A19's, etc and it's senseless to just toss them. We're getting to the point, however, where probably by the end of this year I can start looking for "value packs" of LED's and stock up and then swap out banks of floods, etc. so they look uniform (downlighting in family room and kitchen)

[whit3rd]

Irrelevant, of course; the light is not formed as a beam inside the bulk of semiconductor, but at glued-on lenses. That's only AFTER the light escapes from the solid semiconductor chip.

You'd have to count up all the quantum jumps that produce a photon, and note that less photons than that are seen to light up the room.