Our experiences with LED light bulb replacements

[mouser]

So I have begun experimenting with LED light bulbs to replace my incandescents, and I thought we could use a thread to share thoughts.

Motivations:

First, let me say something about my motivations.  A big appeal of LED light bulbs is their lifespan and low cost of usage.  Those are not primary motivations for me -- mostly because I think with technology changing, a 20+ lifespan in theory is unlikely to be a reality -- new models will be out in 5 years that will demand upgrading.

However, I am motivated by the decrease in heat output -- in the summer my incandescents can generate a large amount of heat and i'm very keen to reduce that.
Additionally, i would like the ability to run brighter bulbs in my existing light fixtures that are currently limited to 60w.

Concerns and Issues:

There are several concerns and issues with using LED bulbs in some light fixtures:

1. Large size of bulbs.  You can get common LED bulbs equivelent to 75w in standard A19 size; brighter than that they get bigger (A21) and may not fit in fixtures.
2. Weight of bulbs.  These LED bulbs can get heavy -- I have one light fixture where I will have to jerry rig some supports for it.
3. Spotlight effect.  The LED bulbs are more directional -- which can be especially troublesome for fixtures where the bulb is pointing up.
4. Color temperature.  There are two main temperatures you see (2700k soft yellow, 5000k daylight blue); The blue LEDS seem like they are closer to flourescent than any incandescent.
5. Candelabra sizes.  I have a couple of chandelier type light fixtures that use candelabra bulbs; there are some candelabra LEDS but it's unclear if they are bright enough.
6. Dimming ability, noise, flickering -- all have been mentioned in various places as potential problem areas for LEDs.

Observations and Recommendations:

I will be posting some initial observations soon -- I hope some of you other early adopters will too -- what have your experiences with LED bulbs been?

[mouser]

Observations and Recommendations:

I installed some CREE 100w LED bulbs (A21 size, somewhat bigger than normal) in two ceiling fan lights (4 bulbs each).
I tried soft white (2700k) and bright white (5000k); the bright white was much too blue.
The soft white was an excellent replacement for incandescents -- very bright, look just like incandescents.

Size was not a problem with one set of my ceiling fan light shades but another set is too narrow and the bulbs don't fit.  Phillips makes a more tubular 100W LED that might.

Dimming was ok but cannot dim to very low light.  Shouldn't be a problem in most cases but if you like to be coy in the bedroom it could be an issue.

[mouser]

Observations and Recommendations:

I did find one very expensive brand of LED bulb that is: 100W bright, suitable for installation in an enclosed fixture, and standard A19 size.
That's a very tricky combination, and you pay for it -- but i do have one kitchen fixture where those features are important.

[though for that price, perhaps the smarter thing to do is replace the light fixture]

[40hz]

However, I am motivated by the decrease in heat output -- in the summer my incandescents can generate a large amount of heat and i'm very keen to reduce that.
Additionally, i would like the ability to run brighter bulbs in my existing light fixtures that are currently limited to 60w.

Those are two considerations I can get behind. Especially the heat reduction part since our AC operation costs did a financial number on us last summer. So anything to reduce BTUs is welcome.

I think if LED does become the dominant home lighting technology we'll see fixtures designed to use them with a far less expensive and kludgey form factor than squeezing them into an Edison style bulb.

When it comes to dimming, I think there will always be a loss of smoothness and subtlety since very few LEDs have variable brightness capabilities. Most dimming will probably be done by switching off elements to reduce overall brightness which is more like a 3-way bulb works with it's fixed brightness levels. Dimmers seem to have largely gone out of vogue anyway.

So yes...please keep us posted on what you discover. Right now I have two LED lamps - both with 60W light levels. I can't say I care for either although the rock solid absolutely flicker-free illumination is nice. And they don't seem to be bothered by the crappy fluctuating voltage levels our local utility company furnishes. Unlike our standard lights which have a tendency to need replacement about every three months because of it.

[barney]

Been using CF and LED bulbs for ~two (2) years.  Garage light is a CF equivalent to a 200W incandescent, but uses between 1/3-1/2 the power.  Several desk lamps with multiple small LEDs, usually ~thirty-six (36) have been working just fine to illuminate various keyboards and desktops.  Not super bright, but adequate.  Have a couple of torchiere floor lamps with variable controls for light levels.  Cannot get super dim, but dim enough, I suppose.  Significant power bill reductions, although I cannot quote values, as this has been happening over time.  Now looking for 100W ceiling fan replacement lights with variable capability.  Also looking for 40W equivalent bulbs for a spider light with five (5) elements and variable lighting, but I suspect that may take a while.  Biggest gripe I have is converting watts to lumens  .

Considering that I'm pretty much planning on dying here, the costs are not significant, since I'll prolly never have to replace a bulb - except for experimental purposes, of course.  Only other LED I need to find is a weather-proof variant for the front porch.  Not difficult to find, but too many choices, so the choices can get confusing pretty quickly.

I wish now that I had kept better track of power and billing as the project grew, but that didn't seem significant at the time  , as that was not a major purpose - I just got tired of replacing incandescents  .

[tomos]

I've only one led bulb at home, but have seen a few elsewhere, and I notice that they never seem to be quite as bright as the equivalent brightness in other bulbs. In one friend's we even reinstated the old bulb to compare - I think it was 60W, and the equivalent-to-60W led was noticeably weaker.
Warm white is definitely a much nicer light too.

[cranioscopical]

A few years ago I swapped all my bulbs (> 100) to CF and found that they came nowhere near to the lifespan indicated, so I'm a  bit skeptical about the promised life of LEDs.

That said, recently I bought 8 60w-equivalent LED bulbs that look like a regular incandescent bulb that's been run over by a steamroller. They're very light in weight, dimmable, and work extremely well as fan bulbs (nothing to be affected by vibration). They also give a good level of light output and I find them more than acceptable in floor lamps. This time round, I'll wait a bit longer before going the whole hog and replacing everything but, so far, I'm very pleased. I'd like, indeed expect, to see the price come down from the $12 each that's being asked right now.

[attach]

[barney]

Haven't encountered those.  Looks intriguing.

[mouser]

There are a few people on youtube doing really good in-depth reviews and comparisons of LED bulbs -- you'll find some reviews of those flat types.

[xtabber]

I have replaced most of the light bulbs in my house with LEDs.  I had been using CFLs whenever possible, but have now gotten rid of nearly all of them because I MUCH prefer the light quality of LEDs. 

LED Prices have come down dramatically in the past year, helped in my area (Massachusetts) by subsidies and rebates from the electric companies: For example, the Philips flat 60W equivalent bulbs Cranioscopical paid $12 for sell for $4.99 at my local Home Depot, as do the Cree 60W bulbs.  Philips A21 100W equivalent bulbs are selling there for $14.99.

3000K is the best color temperature for most LED lighting, IMHO, but it is hard to find in most sizes, 5000K is awful, except for a few situations like workbench lighting.  2700K is the standard for "warm white" incandescents and is fine for most indoor lighting and good for reading.  Most current LED bulbs have a color rendering index (CRI) in the mid 80's, but I have recently found some Feit PAR-20 LED bulbs with a CRI of 93, and the difference in quality is dramatic when they are used to replace LED or halogen bulbs that produce the same nominal light as measured in lumens.  I expect to seem more high CRI bulbs becoming available.

In general, I have found Feit bulbs to be the most reliable and to have the best dimming performance, but I have only seen them in a few sizes, and none above a 75W equivalent.  The Philips A21 75W and 100W equivalents give good light at full setting, but tend to shut themselves down when dimmed.  The 60W flat Philips are very good and I hope that design will find its way into brighter bulbs. I have generally found Cree bulbs to be inconsistent in light output and very poorly constructed.

[4wd]

Replaced all the MR16/GU10 50W Halogens with LEDs, (3-4W), almost all others are CFL.  I don't think I've had to replace a CFL in the last 5-8 years, (they're all used in ventilated fittings that stay on for an hour or two at the least).

I only use LEDs or CFLs with a colour temperature that approximates daylight, (~5000K), as I find the yellowish/reddish hue of warm white annoying, (if I buy a "white" light, I want white dammit!!).

Apart from a driver failing in one of the LED GU10s, (which I replaced), they've been working for the last 4 years or so without problem.  All of the LEDs came from a generic Chinese goods online store, (cheaper than local prices), as either assembled or separate LED/driver/bodies.

I also installed a couple of 10W LED floodlights before leaving the country at the start of April, don't know if they're still working.

[40hz]

The CFLs, which most of my house uses, last about 6 months to maybe a year (under moderate use) where I am. I don't see anything like the five or seven year lifespans claimed on the packages. Could be our local utility is  to blame because they provide rather dirty power and deliver highly fluctuating voltage levels during AC season.

I still worry about the long-term mercury problem however. CFL bulbs just get tossed rather than recycled. It might not be a problem so far. But ten years from now, when billions upon billions of these things are sitting in landfills...

There's been some lame arguments that the reduction in power consumption from CFL bulbs results in less overall mercury being released into the environment in areas where coal-fired generators are the norm - because less coal (which also contains mercury) gets burned. But that sounds more like an industry thrashing around to find something - anything - to throw up against the fact that no level of mercury exposure is ever good for us.

[zenzai]

I still worry about the long-term mercury problem however. CFL bulbs just get tossed rather than recycled. It might not be a problem so far. But ten years from now, when billions upon billions of these things are sitting in landfills...

They're also very poisonous if they break:

http://www2.epa.gov/cfl/cleaning-broken-cfl

[Mad.Diver]

I replaced 13 GU10 Incandescent lamps (a mix of 25 / 50 Watts) in my kitchen with warm white LED spots. Each spot contained 3x1W LED's. The resulting light output was a bit less but still quite satisfactory.

Unfortunately the LED spots have a very limited life. Basically these are Chinese rubbish, the design and manufacturing are really poor. I've had two sets now and in the first set the LED's overheat and eventually one fails causing the drive circuit to destruct. In the second set the LED overheats and fails but the drive circuit survives so I've taken to unsoldering the working LEDs in one broken lamp to replace the failed one in another. It brings them back to life for a few months at least.

The root cause is that they are over-driving the LEDs to achieve light output and this radically shortens the LED life. Typical specmanship over reliability commonly found in cheap Chinese cr*p.

The replacements I'm buying now are a 'known' brand and appear much better but time will tell. Sadly any money or environmental savings have been lost many times over due to the greedy supply chain. So I recommend to spend a little more and avoid 'bargain' prices based upon imports.

[mouser]

Yeah, i figure the boasted lifetime of these LEDs (20+ years) is totally unhelpful -- even if they did last that long, it's inconceivable to me that after 10 years there won't be better technology you will want to replace them with, so calculating the long-term return on investment is a bit tricky.

However, psychologically speaking I do think there is something to be said for paying up front for super-efficient bulbs, in terms of eliminating daily concerns about electricity costs.  That is, i feel better absorbing the psychological pain of spending a large amount to purchase the bulbs up front, and then being able to live my lift not worrying about leaving the lights on all day -- vs. always worrying that i'm wracking up huge energy bills if i forget to turn the lights off.  There is something comforting about removing the voice in the back of your head nagging you to turn off the lights to save electricity

[mouser]

Since we have some lightbulb experts here, perhaps this is a good opportunity for me to ask a couple of questions that i should have asked before i started my journey to LEDs.

I have (ceiling) light fixtures that state very clearly "MAX 60W [incandescent] BULB".  So one of the motivations for me moving to LEDs is the ability to run brighter LED bulbs that give off lumens equivalent to a 100w incandescent.

But to be honest, I don't really know what that limit on the fixture is all about.  I have had a circuit fuse throw once or twice that i attributed to overloading a light fixture with over-wattage bubls.

So I guess my question is -- what exactly are those max wattage limits on the fixtures all about?  What is the danger of putting higher wattage bulbs in there?  Am I right to assume that I can put BRIGHTER LEDs in there as long as the electricity drain is low?  Am I right to assume that the LED bulbs will not generate dangerous heat levels?

[Sarkand]

...However, I am motivated by the decrease in heat output -- in the summer my incandescents can generate a large amount of heat and i'm very keen to reduce that.

I have installed three Kobi (made in China) LED 75W equiv., 5000K, in my room.  One in a floor lamp, one in a table lamp and one in a reading/desk lamp.  I have been very satisfied so far.  I like the bright light - all three are essentially positioned for indirect lighting - but the desk lamp I have used for reading, and it's great.

I have noticed, however, that while the bulb itself stays quite cool (body temp?), the radiating fins at the base become quite hot.  I am not able to touch them for longer than about .5 sec. at a time.  Perhaps this is because of the "made in China" stigma deprecated above, but they have been working very well for several months with no problems.  If what I have experienced is common, you really haven't done a whole lot to reduce total heat output.  I'd like to know if others have detected this high heat of the radiating fins between the base and the bulb itself.

[mouser]

The heat fins do get very hot.. Though that doesn't definitively tell us about heat comparisons.

My limited and shallow understanding of physics does tell me that since the LED bulbs are running so much more efficiently and using so much less energy -- that overall heat output must be significantly less, regardless of whether the fins burn your hand or not

But I could be wrong and I'd love to hear more from people who know.  If I am wrong, then i have just poured a bunch of money down the drain for little good reason.

[CWuestefeld]

Regarding the heat...

Light bulbs are hideously inefficient. Almost 100% of the input energy is converted to heat. And the improved bulb technology (tungsten incandescent -> CFL -> LED) is the result of improving on that efficiency.

But in any case, the amount of energy emitted by a lightbulb in the form of light is pretty tiny. Viewed another way, wiring up fifteen, hundred-watt incandescent bulbs is almost indistinguishable from a space heater. At the end of the day, the amount of heat you're going to generate is pretty much the wattage of the bulb, regardless of technology.

LED bulbs use far less watts, but still get hot. I believe that's because the LED is soaking its heat into a much smaller area. So an incandescent is making more heat and radiating it out through a relatively larger area. An LED makes less heat, by generating a similarly high temperature but radiating it out through a smaller area (so that if you touch a fingertip-sized area of each device, they feel about the same).

[Sarkand]

The heat fins do get very hot.. Though that doesn't definitively tell us about heat comparisons.

My limited and shallow understanding of physics does tell me that since the LED bulbs are running so much more efficiently and using so much less energy -- that overall heat output must be significantly less, regardless of whether the fins burn your hand or not

But I could be wrong and I'd love to hear more from people who know.  If I am wrong, then i have just poured a bunch of money down the drain for little good reason.

I don't remember much of my high-school physics either, and I was mercifully spared in college.  So I may be talking nonsense.  But if I remember what little I do correctly, the total amount of heat generated by any electronic device is a function of its resistance, not the interplay of voltage, wattage and amperage.  The efficiency of the bulb is due to reduction of wattage (don't know about the amperage, input voltage is obviously the same).  But considerable heat can be generated at very low power, if resistance is high enough.  Even a small flashlight bulb gets pretty hot when illuminated for a few minutes.  Indeed, it's the heat produced by resistance that generates the incandescence.  LEDs are more efficient because they use less total power throughput relative to incandescents to produce a roughly equivalent number of photons.  This all seems pretty obvious.  What is not obvious to me is why so much heat is still produced.  Is the LED driver the equivalent of a step-down transformer?  I think that would account for it.

I understand your desire to reduce heat - I have a similar problem in my place in the summer.  I, too, thought they would run much cooler and was surprised to feel the high heat of the fins.  But I wouldn't lament too much if you don't get the reduction you expected - if the bulbs perform as advertised, they will pay for themselves many times over.  And surely someone has made this heat comparison somewhere.  Have to see if I can dig it out.

[mouser]

Fascinating post on electrician forum:

http://www.electriciantalk.com/f8/misconception-leds-produce-almost-no-heat-leds-require-massive-heatsink-24168/

"...Incandescent lamps reject heat through invisible infrared radiation. LEDs dissipate heat almost solely through conduction, therefore it gets hotter at the fixture... "

[mouser]

So this stuff actually gets back to my question:

I have (ceiling) light fixtures that state very clearly "MAX 60W [incandescent] BULB".  So one of the motivations for me moving to LEDs is the ability to run brighter LED bulbs that give off lumens equivalent to a 100w incandescent. But to be honest, I don't really know what that limit on the fixture is all about.

It seems from what I'm reading now that this 60W limit is not so much about electricity limit, but about how much heat the fixture bases can take.  And if that's true, and LED bulbs generate huge heat at the fixture base, I may be in trouble.

Also: http://www.edn.com/electronics-blogs/led-insights/4423570/That-60W-equivalent-LED--What-you-don-t-know--and-what-no-one-will-tell-you-

[40hz]

I just picked up a few of those lollipop-shaped Phillips LED "bulbs" from Home Depot. On sale for $3 and change.

[attachthumb=#]

I have one in the ceiling light over the kitchen sink. It looks nice and doesn't seem to throw any heat.

[attachthumb=#]

Don't know what the base is doing temp-wise. If I ever get my IR thermometer back I'll have to check it. The CFL lamp that was in there has a discolored base from the heat its ballast generated.

Also found this shot of the inside of one of these bulbs.

[attachthumb=#]

Which is great because I was very tempted to crack one open just to see what was inside. $3 saved!

I can't help thinking a time will come when we'll need to liberate these lamps from AC because the inefficiencies of converting 110v down to what the LEDs need is a waste. I have seen some vacation-type homes wired for regular AC (required by building code) and low-voltage DC for things powered by the solar panels on the roof. I think as time goes on we'll see more of this. Possibly with the electrical mains remaining the way they are - but with only a small number of outlets to provide 110v or 220v AC to less efficient devices like clothes dryers, convection and microwave ovens, air conditioners, etc. The rest of the outlets, that power everything else, will be low-voltage DC driven by a single transformer/regulator located in the basement.



---------------

Update: it's been in for a few hours now and it's warm. If I put my fingers on the ring around the 4 o'clock mark, I can keep them there about 3 seconds before I have to move them. It's definitely hot enough to burn.

Oh well! So much for the heat reduction. The CFLs are definitely running cooler. The lamp base is equally hot - but at least the CFL tube was touchable. Not so the LED ring.   

[Renegade]

On the other side of the LED issue...

I do a fair amount of work in the semi-conductor industry, and LED lighting is a good part of that.

Going forward, what you need to be aware of is that LEDs ARE SEMI-CONDUCTORS. This is important.

The capabilities of lighting devices will expand well beyond "lighting" in the future. Any number of different sensors can be included with them.

Expect LED lighting to include more sensors, and to have the capability to spy on you. It will happen. Just keep your eye on the added "benefits" that they tout in their marketing.

I'm well aware that a good number of people here think that I'm a paranoid conspiracy theorist. You wouldn't if you saw what I saw. I get to look at internal documents that aren't public. As an example, I recently had a document come across my desk from a large semi-conductor manufacturer talking about how they were near ready to distribute tracking chips designed to be embedded in people. This is almost not-news at all. It has been reported for many years, and the technology is near ready for large scale deployments.

LED lighting has huge potential. It can recreate what looks like sunlight. The range of light that it can replicate is astounding. The development kits for lighting device manufacturers are becoming more and more robust with lighting being able to be upgraded through simple engine replacements rather than through complete redesigns.

But... it's a Trojan horse. Make sure your horse is empty before you let it through the gates.

[Sarkand]

I don't know if it will be of any consolation, but:  all three of my installations are base-down.  (I use the desk lamp on my nightstand, but rarely read in bed, so it's almost always pointed upward for indirect lighting.)  In this position, the socket fixtures themselves remain at or near room temperature, so the fins clearly do a pretty good job, and I personally would not hesitate to strech 60 to 100 in this configuration.  Base-up?  Perhaps in a ceiling fan that you run all the time when the light is on, forced convection would cool to a reasonable level.  But my fingers tell me that in any shaded base-up installation, it would just have to get damned near as hot as an incandescent, even with otherwise unrestriced airflow.