Recessed lights and attic insulation

• Turn the power off at the breaker before you put a hand in a can. The wall switch is not enough. Let the fixture cool first, because an old one runs hot.
• Never lay insulation over a fixture that is not marked IC. Never wrap one either. That includes loose fill drifting up against it and a batt tented over the top.
• No label, or a label you cannot read, means non-IC. Treat it that way until you have proof otherwise.
• Do not improvise a cover. A cardboard box, a bucket or a rolled batt is not a cover. Use something listed for the job that will not burn, and read the next section before you buy.
• Stop for wiring you do not recognize. Knob and tube, aluminum branch wiring, brittle cloth insulation or scorch marks all mean an electrician goes first.

The rating is printed inside the housing, on a sticker or stamped into the metal. It is usually high up, near the socket, where you can only see it with the trim out. Five minutes per fixture, and it settles the whole question.

1. Switch the circuit off at the panel. Then try the switch to confirm.
2. Let it cool. An old can that has been on runs hot enough to burn a hand.
3. Take the trim out. Most trims are held by two coil springs or by torsion clips. They pull straight down, and the springs stay attached to the housing.
4. Look up with a flashlight. Turn your head and look at the sides of the can as well as the top plate.
5. Photograph the label with your phone. Reach in, shoot upward, and read it later in good light. This is far easier than reading it in place.

What you are looking for is short. The letters IC, or the words insulation contact, mean insulation may touch the housing. The words Non-IC, or a note that insulation has to be held clear, mean it may not. Many labels also print the clearance the fixture needs, and that figure is the one that governs your fixture. Some labels add IC-AT or airtight, which is a second rating and is covered below.

Shape is a hint, not proof. A non-IC housing is usually a single skin of metal with vent slots punched in it. An IC housing is usually double walled, so the outer skin stays cooler. That pattern holds often enough to guess with and not often enough to bet a house on. Read every can rather than judging a whole ceiling from one, because houses get remodeled a room at a time and two kinds of fixture in one ceiling is common.

One reading is always available. Say the fixture is already buried and you cannot find a label. Assume non-IC. Pull the material back off it before you do anything else. The inspection guide covers the rest of the walk through, and what the material is matters here too, because loose fill drifts back against a fixture and batts do not.

This is the point most pages skip, and it is why an attic can pass the fire test and still cost you money every winter.

The model energy code puts a number on the second one. The U.S. Department of Energy's Building America Solution Center brief on recessed lighting cites the 2015 IECC and IRC, at section R402.4.5, and gives the bar as no more than 2.0 cubic feet of air a minute. That is tested to ASTM E283 at 75 pascals of pressure difference. The same brief says recessed lights should be sealed to the ceiling with a gasket or with caulk.

Energy codes cover new building and work done under a permit. They do not usually cover adding insulation to an attic you already have. Which edition applies where you live depends on your state, and often on your city. Your local building department is the only authority on it.

So an old can that is stamped IC is not finished business. Cover it, then go downstairs and seal the joint between the trim ring and the ceiling. That is a tube of caulk and twenty minutes, and it is the cheapest part of the whole job. The next section covers the leak itself, and the air sealing page covers the rest of the ceiling.

A non-IC can is a hole in your ceiling by design. The vent slots are punched into it on purpose, so the heat from the lamp can escape. In a ceiling under an attic, that heat escapes into the attic, and so does the air around it.

Warm indoor air is buoyant, so in winter it pushes up and out through any opening in the ceiling. It carries moisture with it from cooking, washing and breathing. That moisture meets the cold underside of the roof deck and comes out of the air as frost, then as staining, then as mold. So a can light is an energy problem and a moisture problem at once. The air sealing page works through the whole ceiling plane and lists recessed fixtures among the usual leak points. It does not rank them, and neither does this page, because this site holds no measured leakage data to rank them with.

There are two separate leaks in one fixture, and closing one does nothing for the other.

• Through the housing. The vent slots, the screw holes, the socket opening and the cable entry. This is the leak the airtight rating is about, and the only real fix from above is a gasketed cover or a different fixture.
• Around the trim ring. The hole cut in the drywall is bigger than the fixture, and the trim just hides the gap. Caulk from below closes it, on an IC fixture or a non-IC one.

If your ceiling has can lights it very likely has the other usual openings too. The hatch or pull-down stair is the biggest one people can actually see, and a bath fan blowing into the attic adds moisture on top of the leak. Doing all three on one trip costs little more than doing one.

This is not a theoretical rule. It came from a run of house fires in the 1970s, and the federal agency that investigated them published what it found.

In December 1978 the U.S. Consumer Product Safety Commission announced new warning labels for cellulose insulation. By then it held 28 reports naming recessed lights as the ignition source of cellulose insulation fires. It also ran its own test. Staff packed 8 samples of cellulose over recessed lights fitted with the bulb the fixture called for. 6 of them started to smolder in under 8 hours. 2 produced open flame within 11 hours.

By April 1979 the count had grown. CPSC had investigated 51 fires involving cellulose insulation, and found that recessed light fixtures were the ignition source in 31 of them. Warning labels became mandatory on cellulose packages made after 15 October 1979. The advice CPSC gave then is the advice on the bag now: keep insulation at least 3 inches from the sides of a recessed light, and do not put it over one.

The electrical codes carry the same rule. The model National Electrical Code (NFPA 70), section 410.116, carried in the model International Residential Code at section E4004.9 sets the clearance from thermal insulation. DOE's Building America Solution Center brief states it plainly: insulation should not be installed above a recessed luminaire, or within 3 inches of its enclosure, unless the fixture is Type IC. There is a second and separate clearance from wood and other things that burn, which is why a non-IC can is not supposed to be jammed against framing either. Both belong to the fixture's listing.

Both are model codes. Your state or city adopts an edition of them and can change it, so what applies to your house is a local question. The fixture label can also ask for more than the model figure, and where it does, the label wins. Your building department and a licensed electrician are the authorities on both.

Two notes worth carrying. Cellulose was the material in the CPSC fires, but the rule is written about the fixture rather than the material, and it applies to fiberglass and mineral wool the same way. And an LED lamp does not retire the problem. The lamp runs cooler, but the driver sits inside the housing, the listing is unchanged, and the label still says what it said.

Read your label first, then find your row. The rows are ordered so the one that overrules everything else sits near the bottom, where you will still see it.

The recommendation. If the cans are marked IC, insulate over them and spend the saved effort on caulking the trim rings. If they are not marked IC, or the label is gone, changing the fixture is the better answer in most houses. It ends the clearance question, the leak and the doubt in one move, and a canless LED does the work from a warm room instead of a hot attic. Keep the boxing route for the cases it suits: a few fixtures you want to keep, a trim you cannot match, a rented house, or a ceiling you cannot reach from below. And whichever route you take, do it before the new depth goes down, not after. The installation sequence puts fixtures ahead of blowing for exactly that reason.

No price appears in this table. This site holds no measured price for a light cover, a recessed housing, a canless LED or an electrician's hour, so it publishes none. What follows is what each option fixes and what it leaves behind.

A cover is a small box or dome that stands over the fixture and holds insulation off it. Five things have to be true, and the last two are the ones people miss.

1. Listed for use over recessed fixtures. That is a stated use on the product, not something you judge by eye. Read it before you buy.
2. Made of something that will not burn. Mineral wool and coated metal covers are both sold for this. Plastic sheet, foam board and cardboard are not.
3. Big enough for the clearance the label sets, on every side and above the fixture. A cover that touches the can is not holding a clearance.
4. Sealed to the ceiling. Caulk or foam it down around the base. An unsealed cover is a small chimney sitting over a hole, and it can make the draft worse than before.
5. Buried like the rest of the floor. Insulation goes over the cover, level with the material around it. A cover left standing proud is a cold spot with a lid on it.

Two more habits. Do not put a cover over a fixture you have not identified, because you are then guessing at the clearance it needs. And leave a note in the attic, or a photograph on your phone, saying where the covered fixtures are. The next person up there will be blowing insulation, and they cannot see what is under it.

Recessed lights are one of the lines that gets left out of a quote and then found on the day. Four things to ask for in writing.

• A count. How many recessed fixtures are in the ceiling being insulated.
• The rating, read off the labels. Ask for a photograph of one label. A contractor who has been in the attic can get it in a minute.
• What is proposed for the non-IC ones, priced as its own line: covers, replacement housings, or leaving them clear.
• Who is doing any wiring, and whether that person is a licensed electrician.

The failure to watch for is a crew that blows depth across a ceiling without opening a single fixture. The attic then measures correctly, and there are buried cans under it that nobody has looked at. That is the same shape of problem as a blown attic with no baffles at the eaves: the invoice is right and the attic is not.

Reading the labels is a homeowner job, and it is the part with the most value in it. Fitting covers is attic work, so it carries the usual attic kit: a fitted respirator rather than a dust mask, sealed eye protection, gloves and boards to kneel on. The federal OSHA breathing standard binds an employer over its crew. It does not cover you in your own attic, so that part is on you.

Stop and call a licensed electrician for any of these. Knob and tube wiring, which has its own page here. Aluminum branch wiring. Cloth insulation that crumbles when touched. Any browning or scorching inside a can. A fixture with no marks on it at all. This site connects homeowners with insulation contractors, not with electricians, so that is a call to make yourself first. Do it yourself or hire covers the general access questions that apply to any attic job.

This is a fire question rather than an energy one. A fixture not rated for insulation contact needs the clearance its own label sets, which means building or buying something to hold material away from it.

Insulation Report earns a commission if you buy through some of the product links on this page. It costs you nothing extra and it does not change which products we recommend or what we say about them.

• Fire-rated recessed light cover

  Look for Rated for use over recessed fixtures, and sized to clear the housing by the distance the fixture label requires.

  Lets you insulate over the area without burying a fixture that must not be buried.

  Skip it if Every fixture is marked IC, meaning rated for insulation contact. Then insulation goes straight over and covers are unnecessary.

We do not sell insulation and we do not install it, which is why this section can tell you to spend less. Four cases where the honest answer is that there is nothing to buy.

• The labels say IC and airtight, and the trims are sealed. Then this is already done. Insulate over them and move on to something that pays.
• The cans are non-IC, they already have their clear space, and no new depth is going down this year. Nothing is getting worse. Put it in the same visit as the next attic job instead of buying a trip for it.
• You were about to buy covers for a ceiling full of old cans. Price the replacement first. With more than a handful of fixtures, a cover per light plus a day in the attic often buys less than swapping the fixtures does, and it leaves the leak in place. Boxing earns its keep on a few fixtures, not on twenty.
• The attic is already close to the level ENERGY STAR recommends for your climate zone. Within about R-10 of it, more depth pays back slowly, and sealing the ceiling pays better. That threshold is this site's own estimate rather than a measured figure. The depth checker turns a tape measurement into an R-value range, and the R-value page carries the targets.

One thing that is never optional. A non-IC fixture with insulation packed over it is not a slow payback question. It is the case the CPSC fires were about, and it gets cleared whatever else you decide.

• Air sealing an attic, and the rest of the ceiling plane
• The hatch, scuttle or pull-down stair
• Bath fans that vent into the attic
• Insulation over knob and tube wiring
• The order attic work has to happen in
• Adding depth over what is already there
• Cathedral ceilings, and knee walls, where there is no attic to work from
• What each attic job needs, and the specification to look for