# LED shop lights getting hot: normal or electrical issue?



## AM420 (May 8, 2017)

I just installed six 4' LED shop lights in my garage. After they have been on for a while I noticed the metal housing was getting pretty hot. Not so hot that they burn my fingers but hot enough to make me worry. I assumed that since they're LED they wouldn't generate much or any heat at all.

A little info on the setup: I have two rows of lights from one light box. I spliced the wires from box to the first two lights on either side and then linked the rest together from the first fixture in each row. The fixtures have a ground, but the house wiring is old and doesn't have a ground so I just cut it off on the future.

Thanks for any advice.


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## JBrow (Nov 18, 2015)

AM420,

I have some LED lighting experience as a consumer. I must say that there is a good part and bad part to my experience. Over the last three years I replaced most of the frequently used lights in the house and installed recessed LED lights for the workshop.

The good part of my experience is that I like the quality of light produced. I also believe that I have seen about a 10% reduction in the electric bill.

The bad part I suspect goes to your question about heat. Since a LED lamp is an electronic device, it generates heat like most other electronic devices. After having 5 of 11 LED recessed shop lamps fail and one kitchen LED lamp fail (at $30 each), I dug into LED lighting a little. Apparently one reason for failure is excess heat; heat in excess of what the lamp's heat sink can dissipate. In short, too much heat, LED failure.

If your shop lights are in an enclosed housing with a diffusing cover, I might be a good idea to run the lights without the diffusing cover. Doing so should allow some of the heat you are now experiencing dissipate and potentially prolong the life of the lamps. Here a vendor article concerning LED lamp failure…

https://www.shineretrofits.com/knowledge-base/lighting-learning-center/why-do-led-s-fail.html

Since it is fairly easy, reinstalling the fixture housing equipment grounding wire and connecting it to the circuit would ensure an added margin of safety.


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## SignWave (Feb 2, 2010)

LED lights don't radiate heat the way that incandescent bulbs do, but the electronics do produce some heat. If they are not in enclosed fixtures, then the heat should dissipate without any problem. Many screw-in LED bulbs will indicate that they are not suitable for enclosed fixtures, for this reason.

Are your lights mounted in a way that air can circulate around them? If so, I would not expect them to get so hot that you'd have a problem. I have some that are surface mount (touching the drywall ceiling) and some that are hanging on a short chain, both of which seems to be sufficient. The base of the fixture is a bit warm, but not dramatically so.

I don't know if this helps or not…


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## MrUnix (May 18, 2012)

LED's get hot… real hot… particularly the newer high-output ones. If it were not for the heat sinks on the new-fangled bulbs, they would melt.

Cheers,
Brad


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## AM420 (May 8, 2017)

> LED lights don t radiate heat the way that incandescent bulbs do, but the electronics do produce some heat. If they are not in enclosed fixtures, then the heat should dissipate without any problem. Many screw-in LED bulbs will indicate that they are not suitable for enclosed fixtures, for this reason.
> 
> Are your lights mounted in a way that air can circulate around them? If so, I would not expect them to get so hot that you d have a problem. I have some that are surface mount (touching the drywall ceiling) and some that are hanging on a short chain, both of which seems to be sufficient. The base of the fixture is a bit warm, but not dramatically so.
> 
> ...


I assumed they would get warm, but not as hot as they are. They are flush-mounted to the ceiling, so that may be making it difficult to dissipate the heat. They're made to be flush-mounted, but I may try to find a way to let them separate a little with longer screws an shims. I can't take the cover off. They're sealed.

Hopefully these things last a while…


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## htl (Mar 24, 2015)

Very interesting!!!


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## woodbutcherbynight (Oct 21, 2011)

For giggles measure the temp with a infared thermometer. The lights themselves should not be getting hot but the electronics that make the magic work do get hot. Since them make them cheap this is the part of LED's that most often fails. The bulbs should last a long time, this they brag about. The electronics, not so much.


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## MrUnix (May 18, 2012)

> The lights themselves should not be getting hot but the electronics that make the magic work do get hot.


The heat is generated at the diodes N-P junction and then dissipated through the substrate, which is then attached to a heat sink to dissipate it further. The 'electronics' is nothing more than a power supply that reduces the AC line current into a small DC voltage. Most LED manufacturers specify a junction temperature not to exceed 125-150C (< ~300F). Put a bunch of them together, like in the current bulbs, and that is a lot of heat 

Cheers,
Brad


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## papadan (Mar 6, 2009)

I was in a Sams store today and looked at their 4' LED shop lights. They have one on, in the display that has been on for almost 2 years non stop. The bulbs were cool and the top of the housing was just barely warm, no actual heat at all.


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## woodbutcherbynight (Oct 21, 2011)

My shop lights are retrofitted T-10 fluorescent fixtures that have no ballast and two LED light tubes in place of the T-10 bulbs. Both have all the electronics inside the bulb and having been on all day read 88F, shop temp at ceiling height was 80F.

Don't have any of the newer LED only lights to compare with which is why I asked about the actual temperature. I have a attic fan in my eve that comes on at 80F. This keeps the air in the shop moving from the open window through the shop and out the vent. Turn that off and the temp where the lights are goes up with no airflow. This also could be part of your issue with heat. I recently added a window fan which helped airflow as it pushes the air toward the vent.


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## melissag001 (Nov 13, 2018)

I just installed this led light in my bedroom. it is the first light ive ever installed so i am a bit nervous as the lights become ridiculously hot, by hot i mean burning, i have actually burnt my finger on it. can this be normal? i've been avoiding turning on the light at all until i hear from an electrician. i am freaked out! any advice is much appreciated!


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## Scap (Aug 7, 2018)

> I just installed this led light in my bedroom. it is the first light ive ever installed so i am a bit nervous as the lights become ridiculously hot, by hot i mean burning, i have actually burnt my finger on it. can this be normal? i ve been avoiding turning on the light at all until i hear from an electrician. i am freaked out! any advice is much appreciated!
> 
> - melissag001


You're sure that's not a halogen fixture?


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## robscastle (May 13, 2012)

Any chance of sending wqwq on a one way space ship trip into outer space?


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## pottz (Sep 15, 2015)

> Any chance of sending wqwq on a one way space ship trip into outer space?
> 
> - robscastle


who's wqwq buddy? i might want to hitch a ride-lol.


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## splintergroup (Jan 20, 2015)

LED's do generate heat! I used some LED arrays in an early chair side floor lamp project and they get very hot. Get your finger close to the bright part and you will get burned. LEDs do put out a bunch of infra-red and one of the challenges for manufactures is creating the phosphorus coating to not only make a pleasant light color but also not break down from the heat.

Basically the power in = the power out. More of that power is converted to photons (light) with LED's, but the rest is turned into heat. Where an incandescent bulb has a large surface area, an LED is basically a point source so all the heat generated is concentrated. Your fixtures eventually absorb that heat and that is what you are feeling.

An interesting article


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## lumbering_on (Jan 21, 2017)

I was involved in spec'ing out an HVAC for one of our buildings, and it's rather interesting to see how much heat LEDs can generate. A typical LED will generate 85% heat and only 15% light, or 85W per 100W is converted to heat. As 1W = 3.412142 BTU/hr, 85W ~290 BTU/hr.

This is a lot of heat to dissipate through a small LED housing. It's actually enough to maintain a 2 ft3 box at 30F above the outside temp in winter.


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## msinc (Jan 8, 2017)

I don't know about these LED lights and heat…it is definitely confusing to me. Some make a lot of heat, some, not so much. it stands to reason that any time you have to go from AC thru a transformer and get low DC volts you will make heat, but that's not exactly the way it works with LED's. I have a Surefire light to go on a handgun. It is small, but very bright and takes a Cr123 3 volt battery. This thing gets very hot. I have a headlamp that goes on a hard hat for hunting at night, it uses a single 18650 3.7 volt battery and produces ungodly light. It does not get hot at all and is totally sealed up. I have big hexagonal shaped big base bulbs in my workshop that glow like the sun…...they have an internal transformer {have to, as all LED's are DC} and yet they do not get hot. I have several different dive lights that are very bright, they don't get hot and are sealed up very tight to not leak down to 200 feet. I gave up trying to figure it out…some get hot, some don't.


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## basset (Feb 2, 2009)

Some facts about LED lights:

High powered lighting LEDs generate light at a much lower running temperatures than the hot filament used in previous generation bulbs. The hottest outside surface of an LED light bulb is often half the temperature of an equivalent brightness Incandescent or Halogen bulb, and around 20% cooler than CFL bulbs. LED light bulbs might be hot to the touch, but they are nowhere near as hot as CFL, halogen or incandescent bulbs. ... Furthermore, LEDs do not generate heat as infrared radiation like incandescent bulbs. LED bulbs run dramatically cooler than their incandescent cousins, but that doesn't mean they don't produce heat. LED bulbs do get hot, but the heat is pulled away by a heat sink in the base of the bulb.


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## OnhillWW (Jan 10, 2015)

Everything you ever wanted to know about LEDs but were afraid to ask…. Long article and lots of info.

https://www.lrc.rpi.edu/programs/nlpip/lightinganswers/led/abstract.asp

My 2c, perfect shop lights, not affected by cold temps, low energy draw, long life. Heat is the only thing that degrade LEDs so be sure they are installed per instructions. Like anything there are quality units and cheap units, a long warranty from a short lived manufacturer is worthless. I have 3 RAB units outside and they are fantastic, $$$ but once installed worth it.


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## Brawler (Nov 12, 2018)

After reading this thread I went to my shop and touched my 4' LED lights in florescent fixtures with ballasts removed. After being on for about an hour the lights were cool to the touch, and the end where the electronics are were about as warm as my cats tummy. I hope this helps.


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## MrRon (Jul 9, 2009)

I would suspect the "cheaper" Chinese made LED's use transformers that are cheap and generate more heat. The "Surefire" and other battery powered lights, don't have a transformer or voltage conversion circuitry to generate heat, so they are cool operating.


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