Damaged insulation disc inside ceiling light
May 22, 2016 1:41 PM   Subscribe

When replacing the burned out bulbs in one of the ceiling fixtures in our staircase I noticed that the disc of insulation inside the fixture had singed/burned through above both bulbs - here's a picture: http://imgur.com/UT5PgLf Yikes! 2 questions:

1) Is this to be expected or should I be worried about this fixture? An identical fixture in the staircase shows no sign of damage above the bulbs at all.
2) Can I replace the insulation and if so where would I get new insulation? A quick google doesn't show any replacement insulation specially for ceiling lights. The existing disc looks like some kind of thin fiberglass with a layer of foil on top.

Unfortunately I had thrown out the old bulbs already before I thought to check if they were a higher voltage than they should be (one of them had actually broken off from the base when it blew so it was a mess). I'm replacing with CFLs which will hopefully generate less heat (the previous bulbs were incandescent).
posted by blu_stocking to Home & Garden (5 answers total)
Nah, you're fine. Particularly since you're replacing with CFLs. LEDs would be even better and they are priced pretty low these days.
posted by humboldt32 at 1:49 PM on May 22, 2016 [1 favorite]

Don't worry about it. As you are replacing with CFLs, the heat generated will be much less, as you note, and there is no cause for concern.
posted by ssg at 1:51 PM on May 22, 2016 [1 favorite]

I rebuilt similar lights a while ago. The previous owner had installed physically larger higher wattage bulbs that rubbed against the insulation.

I replaced the insulation and recovered with aluminum foil and they have been working like a champ ever since. Used foil backed insulation from a AC duct or similar will work. You can also purchase foil faced insulation and then cut it up to fit.

The CFL produces about 1/5 the heat of the incandescent and an LED build generates about 1/6 the heat. If you stick with the newer tech bulbs I do not think you need to do any repairs at all. I did them because I am terribly anal about such things.
posted by pdoege at 2:48 PM on May 22, 2016

Even for a higher wattage bulb than should have been in there, fiberglass insulation doesn't burn until well over 1000 degrees. The purpose of the foil and insulation is to reflect heat (and light) down, away from the fixture and the wiring. Even so, an enclosed fixture tends to build up a lot of heat, especially with incandescent bulbs.

It seems more likely that someone put oversized bulbs in there and cut away some of the insulation to make more room for that to work, which is a bad idea and potentially a fire hazard. Your picture is an infuriating tease because the label that indicates the maximum wattage is partially visible but the number is obstructed.

The number is certainly at least 40 watts, and more likely 60 or higher. Your new CFL is rated 15 watts, so a lot less heat will be generated. There's almost no risk associated with leaving the fixture as-is with much cooler bulbs, but repairing the foil would be just a little safer, and would also allow the fixture to emit a smidgen more light.

Other than that, the fixture looks like it is in very good condition.
posted by jgreco at 8:21 AM on May 23, 2016 [1 favorite]

Consider replacing the foil if you can find a glue that'll work over a long period of time-- most tape or common household glue would unstick if trapped inside a moderately warm fixture for months.
posted by Sunburnt at 12:44 PM on May 23, 2016

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