Question

Which medium base LEDs can be used in enclosed ceiling fixtures? Most require an open fixture.

Asked by Mouna
New Rochelle, NY

I have 3x60W incandescent lamps in my ceiling fixture. Need to replace them with LEDs. enclosed fixtures a problem for heat?

Answer

David Bergman

Answered by David Bergman

New York, NY

David Bergman Architect

July 28, 2012

I often refer to incandescent bulbs as “toasters” (here and here) because of the amount of waste heat they make and the similar ways the filaments in the two electrical appliances work.

And one sign of the higher efficiency of CFLs is that they aren’t as hot to the touch.

If LEDs are at least as energy-efficient as CFLs, why then is there so much concern over their heat and ventilation? Higher efficiency should mean less waste heat.

LEDs and heat

The answer is that LEDs do indeed make less heat; however, they themselves are more sensitive to heat than their incandescent and fluorescent brethren. (Fluorescents work the opposite way; they are sensitive to cold.) As a result of this sensitivity, a major focus of the design of LEDs has been on heat dissipation. That’s why you’ll often see lots of little metal fins on LED replacement bulbs. Those fins help cool the LEDs.

And that’s also why you’ll often see warnings on LED bulb packages that they are not designed for fully enclosed fixtures such as surface-mounted ceiling lights. Because air does not circulate much in those fixtures, the fins have nowhere to dissipate their heat to.

Heat issue is being addressed

But LEDs are still a developing technology. Lumen outputs are increasing, prices are decreasing and, yep, the heat issue is being addressed.

While you are correct to observe that many LED bulbs will have the warning about enclosed fixtures, there are some newer ones that do not have that restriction.

Suitable for enclosed fixtures

There are probably others out there, but in the standard “A-19” bulb – the kind in which the worst toasters are being banned – I know of at least three manufacturers of bulbs that claim to be suitable for enclosed fixtures:

  • The winner of the recent “L Prize,” made by Philips, is widely available.
  • TCP’s bulbs are also pretty available.
  • Switch has a cool (literally and figuratively) design that incorporates liquid cooling.

Tagged In: led, Green lighting

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