LED Lighting & Energy Efficiency

[TEG]

Not all LED bulbs have heat sinks. It depends on how much you are trying to "overdrive" them.
You can make a bulb with lots of small LEDs placed far enough apart that heat doesn't build up, or you can use one more powerful LED with a heat sink to spread the heat away.
As you start to go above 5W per bulb then heatsinks become commonplace... Under 3W not so much.

 

[shark2k]

Thanks for the responses!

-Shark2k

 

[VolkerP]

One minuscle thing to add: make a distinction between heat and temperature. Heat is thermal energy and temperature is the level of that thermal energy. LEDs are killed at certain Tc. A heat build up equals temperature increases. A heat sink dissipates heat to the environment, lowering temperature at the point where the heat comes from. In the case of shower lights, I guess a retrofit LED with heat sink will not work because the casing is not designed to shed the heat any further.

 

[neroden]

Well, I notice that the home supply places have more shelf space for LEDs, and the prices are slowly dropping.
But instead of new upstart "off brands", you see more from the big companies like Philips and GE.

Yeah. I was buying "Feit" LEDs (they're good by the way), but now the big companies are making the same stuff and driving Feit off the shelf.

 

[neroden]

Not all LED bulbs have heat sinks. It depends on how much you are trying to "overdrive" them.
You can make a bulb with lots of small LEDs placed far enough apart that heat doesn't build up, or you can use one more powerful LED with a heat sink to spread the heat away.
As you start to go above 5W per bulb then heatsinks become commonplace... Under 3W not so much.

The key thing to note in this regard is that typical household bulb replacements (replacing 60 watt or 100 watt bulbs) are at least 6 watts per bulb. Several of the ones I've gotten are 6.5 watts -- they claim to give the same lumens as 40 watt bulbs, but actually they're more like 100 watt bulbs when new.
(The reason for this, I have concluded, is that all of the lumens in the LED are in the visible range, and a lot of the lumens in an incandescent are not in the visible range.)

Only if you're replacing small ornamental bulbs or smaller bulbs in "chandelier" fixtures with numerous bulbs are you going to get bulbs under 3W. (Which I've done.)

I actually replaced all my fully enclosed fixtures so that I could retrofit my house with LEDs. This was probably a good idea. I wouldn't worry about semi-enclosed fixtures, however; I have recessed canisters, and I have lights inside a bathroom exhaust fan housing, and the LEDs (with heat sinks) seem to be happy in both.

I *do* have one question for everyone, however. I have outdoor light fixtures which are designed to take standard A19 bulbs. I can find outdoor-rated incandescents, I can find outdoor-rated flourescents, I can find outdoor-rated LEDs *in other form factors*, but I cannot find an outdoor-rated A19 LED. Does anyone have experience with this, or a pointer? I don't want to replace my outdoor fixtures, and I don't want to destroy my bulbs with moisture and temperature fluctuations. The fixtures are solid on the top, glass on the sides, and open on the bottom (result is that I can't put in anything other than A19 form factor, and I do need outdoor-rated bulbs).

I have kept the light in my stove hood as an incandescent, because I am unsure how masses of grease and hot smoke would affect an LED (probably pretty badly).

Apart from that and the outdoor lights, I'm all LED now. This was actually done not just for energy efficiency. My fiancee is photosensitive and LEDs put out no ultraviolet, unlike CFLs and incandescents. Her first reaction was "the light doesn't hurt!" The energy savings are a nice bonus.

 

[NigelM]

I have kept the light in my stove hood as an incandescent, because I am unsure how masses of grease and hot smoke would affect an LED (probably pretty badly).

I changed mine to LED about a year ago as I was fed up with the additional heat from the halogen spots that I had in there. I've had no problems whatsoever and cooking is much more comfortable.

http://www.superbrightleds.com is a great source for LED bulbs and the also have outdoor and weatherproof rated. A number of Roadster owners have replaced our cabin and license plate lights with LED's from there...everyone was happy with the service and prices. See this thread: Replacing-incandescent-bulbs-with-cool-LED-alternatives

 

[Zextraterrestrial]

Nigel, You don't cook with heat or what? ;>

I like LEDs but hate that I can see them flicker : ( especially the Christmas ones.

 

[TEG]

Nigel, You don't cook with heat or what? ;>
I like LEDs but hate that I can see them flicker : ( especially the Christmas ones.

Some use, what I think is called a "half wave rectifier" to cheaply get choppy DC current from AC so they flicker at 50 or 60hz.
Particularly true with x-mas lights. Ones with better power supplies don't have to flicker like that.
Also, some with dimming functions will use a "chopper" variable power supply that can cause flicker.

 

[NigelM]

Nigel, You don't cook with heat or what? ;>

Haha, I'm 6' and the halogen lamps in the stove hood always seemed to be making my face hot....I like my food hot and not my head. BTW, I've never seen any flicker whatsoever and we're using dimmable bulbs also.

 

[TEG]

...BTW, I've never seen any flicker whatsoever and we're using dimmable bulbs also.

Yeah, some people are more sensitive to it.
Did you ever notice flicker on old CRT monitors?
To me the old 50hz UK CRT TV sets are nearly unwatchable.

Oh, and for dimmable bulbs using a "chopper" variable power supply, the frequency matters. If they use a higher frequency then people are less inclined to notice flicker. Basically, the really cheap ones can cause more noticeable flicker.

 

[Zextraterrestrial]

Haha, I'm 6' and the halogen lamps in the stove hood always seemed to be making my face hot....I like my food hot and not my head. BTW, I've never seen any flicker whatsoever and we're using dimmable bulbs also.

I kind of figured you were probably taller : >
Extra heat in Florida is not as desirable as it is in coastal Humboldt.

I know most/many people can't see the flicker...slower processors maybe : P I think it is only light sources under about 70 Hz that I see usually. On occasion fluorescent bulbs flicker but I think it is only those with non-electronic ballasts. The last CRT I had was ~75 or 80 Hz I think. I don't remember seeing problems on that ever.
The Costco non-dimmable leds that I put in our vanity flicker some (most noticeable w/ running water or other liquid streams ;> Traffic signals flicker & radar feedback signs flicker but I have never noticed vehicle brake lights flicker
Most of the flicker I see is while looking almost perpendicular to the light source

 

[neroden]

I changed mine to LED about a year ago as I was fed up with the additional heat from the halogen spots that I had in there. I've had no problems whatsoever and cooking is much more comfortable.

Good to know. I'm still suspicious since we do a lot of cooking with grease. Do you?

http://www.superbrightleds.com is a great source for LED bulbs and the also have outdoor and weatherproof rated.

No outdoor A19s, though, so no help to me.

 

[NigelM]

Good to know. I'm still suspicious since we do a lot of cooking with grease. Do you?

No deep fat frying here...I've got to be able to squeeze into my Roadster every day.....:biggrin:

 

[Sig698]

I'm eager to switch a lot of my lighting to LEDs, but have yet to find an acceptable substitute. I've tried the Phillips and even they had issues with dimming, and all of the lights that I plan on replacing are on dim circuits. Anyone had decent results? I'm very picky about color reproduction and flicker. For now, I'm holding out with high hopes for Switch bulbs to hit the market: SWITCH

 

[stenkb]

I switched out my entire house to LED dimmable lights - about 150 of em..... sigh... Phillips Dimmable LED - all work great - 95 percent of my houselights are on dimmers. Just make sure you get dimmable led's and should be good - the leds that are not dimmable will burn out fast if on a dimmer - or so I was told....

 

[woof]

Anyone had decent results?

I've had good results with EagleLight Dimmable LED Light Bulbs specifically the PAR 30 spots in overhead cans. Pricy still.

I have them on Smarthome dimmers. No buzzing, dim from about 10% to 100%, no obvious flicker and lots of color temp choices. Did I mention pricy?

 

[Lloyd]

Did I mention pricy?

OUCH! $73.99 for a par30! I'll wait for the prices to come down!

 

[SByer]

OUCH! $73.99 for a par30! I'll wait for the prices to come down!

Yeah, that's the thing. Phillips is on the low-end of the 'acceptable' set of LEDs. Toshiba's PowerCore bulbs do dimming well, but aren't as bright as I'd like. My favorite LED light is a 150w-equivalent flood with a nice 40 degree beam spread over the kitchen sink from LEDWaves. It was $125. It was worth it (!).PolarRay has some good bulbs as well.

If you get a good LED bulb, you can tell. It's a 'happy' light - zero flicker, better color than an incandescent. They're not easy to find or cheap yet.

 

[Sig698]

If you get a good LED bulb, you can tell. It's a 'happy' light - zero flicker, better color than an incandescent. They're not easy to find or cheap yet.

Ouch, that sounds extremely appealing, but not sure I can justify that price when I have 34 recessed can lights to replace!

 

[SByer]

Ouch, that sounds extremely appealing, but not sure I can justify that price when I have 34 recessed can lights to replace!

Yeah, it's still at 'expensive hobby' stage. But then, I refuse to buy any more incandescent or curlies. I toss the incandescents when I can (or when they burn out), keep a couple of curlies as buffer-spares.

It's better than it was - used to be you couldn't find an LED that would actually work as a replacement. And, the ones that do are now less expensive than the ones that weren't just a couple of years ago. Another 2 years...?