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The only place I now use an incandescent bulb is in my oven. It went out the other day and I was looking for a replacement. I am using LED all over these days but realized it may not be possible to use LEDs in a heated environment like an oven. Is that the case, or are there LED bulbs for that now also?

Christian
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    Bear in mind that if you've got an electric oven, the amount of power the bulb is using is effectively zero compared to what the oven is using for cooking. Switching from incandescent to LED will provide such a negligible savings in electricity or cash that you'll likely _never_ notice. – FreeMan Apr 14 '21 at 13:36
  • Also, if it's a gas oven, the amount of time the light is on is still minimal and the electricity use/cost difference between incandescent & LED is still going to be pretty darn small. – FreeMan Apr 14 '21 at 13:55
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    From Ye Darke Ages of 2020: [Can LED Bulbs Be Used In Ovens?](https://ledlightinginfo.com/can-led-bulbs-be-used-in-ovens) – HABO Apr 14 '21 at 15:29
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    @HABO "Without a light in the oven, opening and closing the oven door to check if the food is done will ruin your dish. Apart from being completely unable to see how brown the top of your cheese casserole has become..." Site looses all credibility with that statement. My oven doesn't have a window in the door. The only way to check on the food is to open the door, and trust me, after 28 years, we've never ruined dinner by checking on it. Occasionally by _forgetting_ to check on it, but never by opening the door. LEDLightingInfo.com should stick to light bulbs and leave the cooking advice alone – FreeMan Apr 14 '21 at 16:39
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    Yeah, that blog is awful. So many inaccurate/half-truth statements. "self care" - is this an oven (self-**clean**) or talking about someone learning to brush their teeth? Don't get me started...oops, too late. – manassehkatz-Moving 2 Codidact Apr 14 '21 at 19:16
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    Mass-produced LEDs are bonded in plastic or epoxy with cannot take the heat. – dandavis Apr 14 '21 at 22:00
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    @FreeMan in an electric oven, it's actually zero - the waste heat ends up in the oven helping to cook the food (leaving the light on is sometimes used to provide a warm place for proving dough. In a gas oven, some tiny fraction of the energy consumption is shifted from gas to electricity – Chris H Apr 15 '21 at 10:05
  • One of the reasons why I like LEDs is that they are much more long-lived than light bulbs. The bulb in my oven has worked for maybe three years before dying; while the LEDs at the ceiling haven't failed since I got them. I accept that LEDs are not suitable for ovens; but I still think that the short-livedness of oven bulbs is a nuisance. – oliver Apr 15 '21 at 14:38
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    @oliver Get a xenon bulb. They'll last almost forever. – J... Apr 15 '21 at 18:03
  • @FreeMan: Opening and closing the over door _can_ ruin some dishes that are extremely sensitive to changes in temperature while cooking - but, yeah, it won't be a problem for the vast majority of your cooking. – Vikki Apr 17 '21 at 00:47

5 Answers5

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As already stated, LEDs can't take the heat. In addition:

  1. Many ovens use halogen bulbs instead of "ordinary" incandescent bulbs. These are a type of incandescent light with two key differences: size and heat.

    The size is irrelevant for most ordinary lamps but great for an oven, where you want something small so that it won't take away from valuable interior cooking space.

    The heat is a huge problem for ordinary lamps, to the extent that there were major recalls/design changes many years ago because of halogen lamps setting curtains and other stuff on fire, resulting in metal grid covers for those lamps and eventually they disappeared altogether in favor of much more efficient CFL and then LED lamps. But heat is perfectly fine in an oven, where you have a high-but-regulated temperature. If you have the light on while cooking and it puts a few extra watts of heat into the oven, the element will turn off a few seconds earlier and the net energy usage is a big fat 0.

  2. In general with any lighting system, the efficiency is a balance between light and heat. All the energy not turned into light becomes heat. In an oven that is perfectly fine and useful instead of wasteful. For an extreme example of this, where the light bulb is the heating element, see the Easy Bake Oven. In fact, for a conventional electric oven, heat generated from a light bulb is essentially the same efficiency as heat generated from heating elements. Where energy usage is a bit different is with microwave ovens and gas ovens.

Machavity
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manassehkatz-Moving 2 Codidact
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    They solved the heat problem of halogens by putting the halogen capsule inside of a standard glass bulb -- most (all?) of the ["energy efficient" incandescent bulbs](https://www.amazon.com/GE-78798-12-Halogen-Crystal-72-Watt/dp/B00GM0XYOQ/) (i.e. 100W equivalent using 72W of energy) are halogen bulbs inside of a standard size bulb, with the same (well, a bit less) bulb temperature as the regular incandescent would have had. – Johnny Apr 14 '21 at 22:10
  • @Johnny that's partly about the heat but largely about the UV. Small halogen bulbs use a quartz envelope that's transparaent to UV, unlike normal glass, and the hotter halogen lamps produce more UV than normal incandescent bulbs – Chris H Apr 15 '21 at 10:06
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    This captures the key point that it's absolutely irrelevant whether it's possible or not because it's not even a problem that requires solving - no heat is wasted because you want the oven to be hot anyway. If you remove the lightbulb, the elements will just work a bit harder to make up the difference. – J... Apr 15 '21 at 10:52
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    The heat of an incandescent bulb is not just OK in an oven, it's even a feature. Sometimes when the kitchen is just a little cold, the oven light is all it takes to make the oven a good place to proof dough. – Wayne Conrad Apr 15 '21 at 20:30
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    An incandescent light bulb is just a heating element that's been put in a vacuum so it can reach the same temperature as the surface as the sun, and thus emit light is the same general spectrum as the sun. – Acccumulation Apr 17 '21 at 15:12
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Not gonna happen. Can't take the heat.

Those consumer products one calls an "LED light bulb" is a built consumer product made of components - case, heat sink, electronics and an array of LED emitters. The latter are purchasable as components by electronics supply houses such as mouser.com, with over 100,000 types listed. Every one has a data sheet.

You (the builder) merge the LED with a heat sink (probably of your own design). To guide heat sink design, the data sheet calls out thermal limits at the point where the LED meets the heat sink. You can't let the LED get any hotter than that.

Those limits are typically 85C, or in rare instances, 115C. This isn't even 250F. That's not gonna work in an oven.

So that's the end of that. CFLs have similar problems, more owing to the survivability of their electronic ballast.

Incandescent bulbs love heat, so it's not a problem.

Incandescent bulbs require heat to function, and if it isn't already in the environment, they have to make it. They self-regulate and don't need a driver/ballast. So they run very happily in hot places.

It's a match made in heaven, and there's no reason other than OCD/aesthetics to want to reinvent that wheel. (and if you really, really, really wanted to, then "light pipes").

Keeping in mind that oven lights are only on when the oven door is open (and often, when the oven is turned on). So the energy use is trivial, and one would be hard-pressed to save a penny's worth of electricity over the life of an oven. Any effort to "greenify" or "increase efficiency" would be better spent anywhere else. Anywhere. Honestly.

Harper - Reinstate Monica
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    "oven lights are only on when the oven door is open" This is only true for ovens without windows. Every house I've lived in has had an oven with a window and the light was controlled by a switch, not by the oven door. – Dan Henderson Apr 14 '21 at 21:45
  • Actually in my oven (Kitchenaid), the lights are controlled *both* by a switch and by the door - i.e., you can lights when you open the door or all the time, your choice. Except the little halogen bulbs burn out too quickly and so I haven't bothered to replace them in years. The other good aspect of LED bulbs - longevity - would be wonderful in an oven, but the LEDs really can't take the heat. – manassehkatz-Moving 2 Codidact Apr 14 '21 at 21:53
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    Every oven I've ever owned has a light that is permanently on, when the oven is switched on. – SiHa Apr 15 '21 at 16:16
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    In UK/European models the light is always on, but I haven't seen an oven of recent design without glass on the door. The thermostat on many models has a position that leaves the light on but the element off - that's handy for proving dough, or as a visual reminder when using carryover heat to finish cooking. Making the user let the heat out to illuminate the contents would be pretty dumb if there's a window - a major reason for having a light at all is to look inside with the door shut. – Chris H Apr 16 '21 at 12:06
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I think it's unlikely that this is possible.

The environment in the oven in quite mild compared with an incandescent lamp, but LEDs, being semiconductor devices generally don't function well above about 100C.

Some vendors seem to be making newer ovens with insulated or otherwise thermally isolated lamp compartments so that they can install LED lighting but generally replacing a standard incandescent bulb in an oven with an LED one will not work.

jwh20
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    I agree with electronics and heat are not a good mix. I looked and find some oven rated lamps but they were only rated to 300 degrees so that’s not very useful in my opinion. – Ed Beal Apr 14 '21 at 13:31
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    @EdBeal what sort of degrees? 300°C would be fine – Chris H Apr 15 '21 at 10:07
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    @EdBeal unless your oven has a "burn-cleaning" functionality, it will very likely be fine as I've never had my oven above 275 degree, and that exclusively for Pizza. Also: those ratings are just what the manufacturer gives the guarantee for / has tested it. Chances are good that it'll take 350 degrees as well – Hobbamok Apr 15 '21 at 11:59
  • @hobbamok, I believe that was degrees F not C today when I looked again I did not see that lamp all the ones 120v rated were for refrigerators or microwaves. Solid state electronics are affected by heat the main difference in some devices is the difference of the thermal packaging and heat sinks. There are thermoelectric cooling devices that may make it possible to cool the semiconductors to allow them to function in high heat but then the efficiency would be lost and that technology is expensive and probably won’t make it into such a low volume device. – Ed Beal Apr 15 '21 at 13:25
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    @EdBeal oh, I assumed Celsius, because when you're already at 300 C, its not a regular lamp and should be fine. But if that's Fahrenheit it's just about 150 Celsius, which sounds like a "generously resistant consumer light bulb" – Hobbamok Apr 15 '21 at 13:48
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    Also: there is 0 reason for efficiency when lighting an oven. Optimizing for it is just plain wasted money, so that is probably the one area where they'll stick with incandescent for a looong time – Hobbamok Apr 15 '21 at 13:50
  • I did suspect as much - after all LED lamps are soldered together, and I've used my oven to melt solder in the past – Chris H Apr 16 '21 at 12:02
  • LEDs are typically only rated for a limited temperature range compared to other semiconductor devices--many of them are only rated to 85 °C, which is far too low for an oven! – Hearth Apr 17 '21 at 05:46
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Even if you could, I wouldn't trust that the plastics, solder and semiconductors of an LED lamp wouldn't leach unfriendly chemicals out into the oven's air, and then into the food. There's a reason they tell hobbyists to not use food ovens for "re-flowing" (building or fixing) electronic circuit boards.

kackle123
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  • Tin/silver solder melts in the 420-430 F range and lead-based solder at ~360 F, so it *definitely* wouldn't end well in an oven. Even if you avoided the fumes, the whole thing would just melt apart. – bta Apr 17 '21 at 03:33
  • And I seriously wonder about the "greenness" of LED bulbs, anyway. Incandescent bulbs are made of metal and glass, that's it--arguably natural materials. There are so many laborious steps and (sometimes poisonous) chemicals that go into making everything involved in an electronic circuit like an LED bulb. Does their _total_ energy use, pollution creation and expense beat that of incandescents? Everyone assumes, no one knows. – kackle123 Apr 17 '21 at 16:25
  • The main reason for not using a food oven for soldering is the flux, which you don't want to ingest either through your lungs or digestive tract, or skin, for that matter. Over on Electronics.SE: [Are solder fumes bad for me?](https://electronics.stackexchange.com/questions/1904/are-solder-fumes-bad-for-me) – Andrew Morton Apr 17 '21 at 19:23
  • @Andrew Morton Good point. – kackle123 Apr 19 '21 at 14:47
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If you want to save energy, you may start from reconsidering the oven itself. It's most likely electric, so basically a huge light bulb, 1000 times greater than the small one you are trying to replace.

And yes, such a replacement is possible. Not with an LED, but there are (gas discharge) lamps with similar efficiency and high operation temperature. They also work much longer (like 10 times).

qduaty1
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