# LEDs for domestic lighting? **URL:** \ **Category:** Factual Questions\ **Created:** [December 22, 2007, 5:39pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944 "2007-12-22T17:39:35Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ticker](https://avatars.discourse-cdn.com/v4/letter/t/d07c76/32.png) [@ticker](https://boards.straightdope.com/u/ticker)\ **Post date:** [December 22, 2007, 5:39pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/1 "2007-12-22T17:39:35Z")
Will LEDs become cheap enough to replace domestic light bulbs? How would they compare efficiency-wise with the mini fluorescents I have now? I don’t expect to need to replace a bulb again for some time given the 8 year lifespan claimed but it sure would be nice if, when I do, they didn’t have that annoying warm-up period. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [December 22, 2007, 6:26pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/2 "2007-12-22T18:26:10Z")
You can make the argument that they are already there. According to the number’s I’ve seen, when you just look at the cost of the bulbs themselves, LED bulbs cost about as much as regular incandescent bulbs in the long term (CFLs are cheaper in the long term). However, when you also factor in the cost of electricity and how much is saved there, LEDs work out to be less expensive than both incandescents and CFLs. The only “problem” with LEDs right now is that you’ve got this huge up-front cost, and then savings in the long term, and that up-front cost is a bit steep for most folks. The cost of LED bulbs is dropping and will (IMHO) likely continue to drop. Give it another couple of years and that huge up-front cost won’t be quite so painful. ---
**Author:** ![Myglaren](https://avatars.discourse-cdn.com/v4/letter/m/f1d935/32.png) [@Myglaren](https://boards.straightdope.com/u/Myglaren)\ **Post date:** [December 22, 2007, 6:39pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/3 "2007-12-22T18:39:18Z")
I’ve just, somewhat experimentally, installed and LED GU10. It isn’t very bright compared with the incandescents and is very blue, although I chose the white rather than the bluer one. It was the same price as the LEF variant. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [December 22, 2007, 7:14pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/4 "2007-12-22T19:14:24Z")
I bought a couple for locations where I needed a not-very-bright bulb and the bulb was hell to replace. Cost was around $20. ---
**Author:** ![Satellite\_Guy](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Satellite\_Guy](https://boards.straightdope.com/u/Satellite_Guy)\ **Post date:** [December 22, 2007, 7:16pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/5 "2007-12-22T19:16:48Z")
I heard (read?) somewhere that fluorescent bulbs are still more efficient than LED’s, so I imagine there’ll need to be some improvement there, before it’s a feasible option. I know that LED’s can warm up quite a bit, and, of course, so do incandecents, but, when I was working in shop class in high school (building a shed, and I was sitting on its roof), I could put my hand around a fluorescent bulb, and it was comfortably warm, not hot… (a testament to its efficiency) Just my $.02… S^G ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [December 22, 2007, 8:35pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/6 "2007-12-22T20:35:31Z")
I read that laser diodes are generally more efficient than LED’s and are likely to replace LEDs as the commonest indoor lighting at some point (or if LED’s don’t replace CFLs, then likely to do that). ---
**Author:** ![chorpler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chorpler/32/2888_2.png) [@chorpler](https://boards.straightdope.com/u/chorpler)\ **Post date:** [December 22, 2007, 8:51pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/7 "2007-12-22T20:51:54Z")
[QUOTE=Satellite^Guy] I heard (read?) somewhere that fluorescent bulbs are still more efficient than LED’s, so I imagine there’ll need to be some improvement there, before it’s a feasible option. I know that LED’s can warm up quite a bit, and, of course, so do incandecents, but, when I was working in shop class in high school (building a shed, and I was sitting on its roof), I could put my hand around a fluorescent bulb, and it was comfortably warm, not hot… (a testament to its efficiency) Just my $.02… S^G [/QUOTE] All of my compact fluorescents get hot enough to burn my hand. Grumble. On Mythbusters, they did a test once where they attempted to measure whether it was cheaper to turn the lights off when you leave the room, or just to leave them on. They looked at two potential reasons why it might be better to leave the lights on: 1) The start-up surge of electricity could be so much higher than regular operating current that it might be cheaper to avoid it by leaving the lights on, and/or 2) The on/off cycling could shorten the life of the bulb enough that it would be cheaper to waste the electricity and extend the lifetime of the bulb. They tested a regular incandescent bulb, a compact fluorescent bulb, an LED bulb, and I think some other bulb I don’t recall the type of. From their data, it looked like the LED bulb used only a tenth of the power of the CFL bulb, and something like 1/60th of the power of the incandescent bulb. Also, it was the only bulb to survive being flicked on and off every few seconds for weeks. I was intrigued. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [December 22, 2007, 9:49pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/8 "2007-12-22T21:49:10Z")
[QUOTE=Satellite^Guy] I heard (read?) somewhere that fluorescent bulbs are still more efficient than LED’s, so I imagine there’ll need to be some improvement there, before it’s a feasible option. I know that LED’s can warm up quite a bit, and, of course, so do incandecents, but, when I was working in shop class in high school (building a shed, and I was sitting on its roof), I could put my hand around a fluorescent bulb, and it was comfortably warm, not hot… (a testament to its efficiency) Just my $.02… S^G [/QUOTE] The temperature of the bulb may not be the best estimate of its efficiency. Just measuring what I have around the house, a 40 watt four foot long fluorescent tube has 85 square inches of surface area, or just under half a watt per square inch of surface area. I have a LED around 0.150" in diameter rated at 60 milliwatts, which works out to be 3.4 watts per square inch of surface area. All other things, including efficiency, remaining the same, you better believe the LED is going to get hot. ---
**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\ **Post date:** [December 22, 2007, 9:57pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/9 "2007-12-22T21:57:59Z")
Missed the edit window. Assuming the coil I have in this CFL is around 18" long, which it is, give or take, and its diameter is 1/2 inch, its watts per square inch are almost the same as the LED, around 3.4. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [December 22, 2007, 10:17pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/10 "2007-12-22T22:17:19Z")
I’m a bit of an LED fan and I have a special interest in household applications. My understanding is that the white LEDs are not yet efficient or inexpensive enough to be a viable replacement for conventional lighting (incandescent and fluorescent). However, for applications using colored light or where replacement is inconvenient or where dead bulbs create a hazard, they come out ahead. One common use is in traffic signals where all three benefits apply. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [December 22, 2007, 10:31pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/11 "2007-12-22T22:31:18Z")
[QUOTE=jnglmassiv] white LEDs are not yet efficient or inexpensive enough to be a viable replacement for conventional lighting (incandescent and fluorescent). [/QUOTE] Not only that, but - speaking only for myself - I don’t like the light given off by “white” LEDs. I once had an LED flashlight. It was very bright. But I hated the color of the light. And in the woods the light didn’t penetrate the darkness very well. I threw it away and got one with a Krypton bulb. The batteries may not last as long, but the light it puts out is _ **much** _ better than the LED flashlight. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [December 23, 2007, 1:27am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/12 "2007-12-23T01:27:32Z")
For light bulbs, instead of using white LEDs, why can’t they use three (or more) different colors of LEDs to simulate white light, within a frosted bulb? ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [December 23, 2007, 1:36am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/13 "2007-12-23T01:36:43Z")
I bought [several of these bulbs](http://www.ccrane.com/lights/led-light-bulbs/index.aspx) (specifically the PAR20 & 30) to see if I could make the switch to LED household lighting. As others have already said, the temperature of light is unappealing. It looks like a bulb that you might find suitable for use in a nightstand lamp next to a hospital patient who is recovering from eye surgery. The light is feeble & sterile. I ended up sticking them in a utility closet. The “suns dusk” bulb looks like it might have a warmer light but I rejected that one due to insufficient luminosity (only 26 lumens!). A standard 60 watt incandescent bulb cranks out about 800 lumens. The under cabinet lighting bars look promising but at $120 for the smallest section, I’m not ready to do any more experimenting at the current prices. ---
**Author:** ![Sockmunkey](https://avatars.discourse-cdn.com/v4/letter/s/f17d59/32.png) [@Sockmunkey](https://boards.straightdope.com/u/Sockmunkey)\ **Post date:** [December 23, 2007, 4:36am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/14 "2007-12-23T04:36:10Z")
Don’t forget the “oops” factor. An LED is going to survive mishaps like being dropped much better than a standard or CFL bulb. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [December 23, 2007, 7:32am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/15 "2007-12-23T07:32:23Z")
When will they be able to work out the shimmer, or is that just a mark of cheap LED “bulbs”? ---
**Author:** ![neutron\_star](https://avatars.discourse-cdn.com/v4/letter/n/51bf81/32.png) [@neutron\_star](https://boards.straightdope.com/u/neutron_star)\ **Post date:** [December 23, 2007, 7:48am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/16 "2007-12-23T07:48:07Z")
[QUOTE=ZenBeam] For light bulbs, instead of using white LEDs, why can’t they use three (or more) different colors of LEDs to simulate white light, within a frosted bulb? [/QUOTE] The first white LEDs were made this way with red, green, and blue, but that costs too much compared to the current method, which uses a blue LED with a yellow phospher coating. An even [newer technique](http://www.livescience.com/technology/051021_nano_light.html) involves coating a blue LED with quantum dots that glow white in response to the blue light. This is supposed to produce a color much closer to incandescent bulbs. > [@gotpasswords](#): > > When will they be able to work out the shimmer, or is that just a mark of cheap LED “bulbs”? What shimmer? I can’t say I’ve ever noticed that. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [December 23, 2007, 4:14pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/17 "2007-12-23T16:14:23Z")
[QUOTE=neutron star] The first white LEDs were made this way with red, green, and blue, but that costs too much compared to the current method, which uses a blue LED with a yellow phospher coating. [/QUOTE] I don’t think cost was the determining factor. The problem was trying to balance the three colors. It’s not as easy as it sounds… the sensitivity of your eye is a function of wavelength (i.e. color), so each of the three colors must be driven at a different intensity. Furthermore, the I-V characteristic curve of an LED is a function of temperature, so the drive current to each LED would have to depend on temperature. And aging will change the I-V characteristics, too. Without a complicated feedback mechanism inherent in each LED, pulling this is off is nearly impossible to do. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [December 23, 2007, 4:27pm UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/18 "2007-12-23T16:27:59Z")
[QUOTE=neutron star] What shimmer? I can’t say I’ve ever noticed that. [/QUOTE] **Gotpasswords** may be referring to the fact that some LEDs have a pulsed output. It shows up during saccadic eye movement. ---
**Author:** ![Sockmunkey](https://avatars.discourse-cdn.com/v4/letter/s/f17d59/32.png) [@Sockmunkey](https://boards.straightdope.com/u/Sockmunkey)\ **Post date:** [December 24, 2007, 8:37am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/19 "2007-12-24T08:37:19Z")
[QUOTE=Crafter\_Man] I don’t think cost was the determining factor. The problem was trying to balance the three colors. It’s not as easy as it sounds… the sensitivity of your eye is a function of wavelength (i.e. color), so each of the three colors must be driven at a different intensity. Furthermore, the I-V characteristic curve of an LED is a function of temperature, so the drive current to each LED would have to depend on temperature. And aging will change the I-V characteristics, too. Without a complicated feedback mechanism inherent in each LED, pulling this is off is nearly impossible to do. [/QUOTE] Would using a cluster of LEDs with more of some colors and less of another solve this? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [December 25, 2007, 12:45am UTC](https://boards.straightdope.com/t/leds-for-domestic-lighting/430944/20 "2007-12-25T00:45:46Z")
[QUOTE=Squink] **Gotpasswords** may be referring to the fact that some LEDs have a pulsed output. It shows up during saccadic eye movement. [/QUOTE] We have a winner! I’m one of those people that sees the “rainbow” effect on older DLP projectors, and if I look quickly across a black and white image on a plasma TV, I see yellow flashes. To me, a lot of LED lights shimmer or even seem to vibrate and move. The multi-color Christmas lights are particularly bad at this - my neighbor’s house across the street looks like it’s squirming right now.