In looking at the selection at Lowes the other day the CFL bulbs were all being closed out at knock down prices and it seems like there is now an LED bulb for almost every application where a filament or gas sealed bulb was used.
For the latest current technology LED bulbs, other than applications where the bulb is being used less for light and more for heat generation, are there any applications where LED bulbs are still inferior to non-LED bulbs?
anything above 100W equivalent, in a standard “Edison” base. I haven’t seen any yet.
I don’t think that there are any 200W-equivalent (3200 lumen) Edison base LED lamps yet, at least not from any major manufacturers.
There are these. The largest have a larger “mogul base”.
Like I said - not a major manufacturer, and WAY bigger than a 200W incandescent lamp, so probably not a drop-in replacement for many applications.
Price is a major concern for lots of people. So the most economically effective approach for lots of applications is CFLs (or incandescents if you still have them around). I only have 3 LED lightbulbs as it doesn’t look economically advantageous to replace any of my other bulbs).
LED 60 watt equiv bulbs are around $2.50 - $3.00 each on sale almost any odd weekend in the US at big box hardware stores. How can this not be economical? At that price point I tossed all the CFLs and went LED throughout just so I would not have to replace dead bulbs.
Photography ??? Is that just a lag in existing lighting equipment, or is it going to take a while for camera’s programmed for LED lighting are in common use?
Fiber optic light guides that are grouped around a single light bulb (like in some auto’s instrument panels). I replaced the somewhat yellowish light bulbs in my Scion’s panel with the LED replacements. The bright white light (or whatever color you want) is really neat, but they only illuminate a portion of the lettering on the panel because they mostly emit light straight ahead.
It is a known problem on the Scion boards and they recommend roughening the LED sides with fine sandpaper to eliminate some internal reflection.
Obviously this is a basic design problem and can be easily overcome with a different design panel.
Dennis
Even cheaper than that here at Home Depot. You can get Phillips bulbs for $2 a piece in a four pack but, better get, there’s some generic-sounding brand I’ve been buying there where it’s $5 for a four-pack. I stocked up and replaced practically the whole house. They’ve gotten cheap.
GE and Feit 150W 3-way bulbs. But I haven’t seen 200+W.
They’re both A21, as compared to A19. Same base (standard Edison), but the bulb is somewhat larger. Probably not an issue, since 150W incandescents should already be in larger housings (given their heat output).
So far, I have not found a GU10 LED bulb that is as good as the old halogens. Specifically, the halogens had a partially-silvered reflector that gave off a pleasing backscatter effect. No LED replacements that I’ve seen match this.
For applications where a proper black body spectrum, or indeed any continuous spectrum is needed, incandescent lights are going to be needed for some time to come. This can include critical photography. Whilst it is possible to perform reasonable corrections to images to balance out the worst of the colour artefacts from LED lighting, it is not possible to achieve perfect results. Laboratory applications such as adsorption spectrography is an obvious place you can’t just slot in a LED.
How about high-temperature applications? Are there LED bulbs that can be used in ovens?
While the high output LEDs are available, the 150w and 150w 3-way bulb seem to go for about $20-25 a piece, while an incandescent is $2-3.
9-10x the price is not what I see as a manageable price point. At $4 a piece, they’ve beaten the 60w game, but the high output price point isn’t there.
Sucks because I use 150w+ bulbs in 7 fixtures around my house, and I’m not investing $150 in replacing the bulbs when I only spend $15 a year replacing them now.
About LEDs having lower wattage: Do they tend to have lower lumens? Wouldn’t a 60W LED produce more light than a 200W incandescent light bulb? Wouldn’t a 100W LED produce about as much light as a 200W CFL? Is there a reason that LEDs can’t be easily joined together to create commensurately higher lumens?
I remember many years ago (15?) indoor cannabis growers flirting with LED arrays for early vegetative growth. The fluorescent aficionados were in a tizzy.
Several power LEDs can produce over 1,000 lumens at very high efficiency:
The highest-output single LED (Cree XLamp XM-L2) can now produce about 1052 lumens, at about 170 lumens per watt. http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Discrete-Directional/XLamp-XML2
Cree XLamp XPL can produce 1,150 lumens at 10 watts (161 lumens per watt), and exceeds 200 lumens per watt at lower output levels: http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Discrete-Directional/XLamp-XPL
LED chip arrays can produce up to 18,000 lumens at 150 watts: http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Arrays-NonDirectional/XLamp-CXA3590
By contrast, the efficiency of a typical incandescent bulb is 16 lumens per watt.
Typical CFL efficiency is 50-70 lumens per watt. A thin T5 tube can produce 100 lumens per watt.
The biggest problem with retrofitting higher-power LEDs is cooling. The most efficient LED is still throwing away about 50% of the input power as heat, since max efficiency for a white light LED is about 400 lumens per watt.
Unlike an incandescent bulb which can radiate away much of its heat in the beam, LEDs have a cold beam and the waste heat must be carried away via conduction. That is why a high-power LED flashlight often gets very hot to the touch.
In retrofit situations the trick is how to fit a higher-power LED into the existing fixture yet still conduct away the generated heat. This is done in various ways – cooling fins, little fans, etc.
Presumably in the future lighting fixtures designed for high-power LEDs will have features to facilitate heat removal by conduction.
The other reason is that LEDs are far more susceptible to damage from heat. Incandescent bulbs can withstand high temperatures - the filament is supposed to get up to several thousand degrees C, and the glass can withstand pretty high temperatures too. The LED emitter is a semiconductor, and is easily damaged by heat. At much more than 100C, their lifetime is very much reduced. That’s the temperature of the actual junction that emits light, not the LED package or the heat sink.
Often when you see clusters of LED lights (e.g. traffic lights), the ones towards the center have failed. It’s because the central LEDs get hotter.
We did all leds in our new house, but I’ve gone back to incandescent in a couple of places where I wanted to be able to dim the lights all the way. The leds just don’t operate right for full dimming.
I know it doesn’t help to say this, but that’s not an intrinsic limitation of LEDs. It’s a limitation of the control circuit built into the “dimmable” LED bulb. LEDs themselves can be dimmed to arbitrary low brightness given a low current supply - here’s a demonstration.
Also, the use of dimmers on LED bulbs is a kludge - we’re stuck with dimmers designed for incandescent bulbs, and “dimmable” LED bulbs that try to emulate the behavior of incandescent bulbs. It would be far better if we provided full power to the “bulbs” all the time, and send digital signals to them to control the brightness. (There are products like that already, like the Philips Hue series, but they’re still expensive and different brands are incompatible with each other.)