Recessed Light Cover

Bendable and can be sliced for the wire

Depends on the manufacturer of the fan. Some light boxes (incandescent bulbs) and I would imagine some home electrical items can give off a large amount of heat over time and warn the user not to cover the rear of the unit with insulation. From my understanding, this product was meant for light cans.

Wood would cost more than these in material and time. The idea behind these is to air seal your home. Also if they were built or wood someone would likely think they could step there. Oooops

Yes, these covers should work well for that issue. My problem was the reverse, in winter time cold air in the attic in combination with warm air in the room caused condensation. Used this exact cover plus some "Great Stuff" foam sealant and problem solved. Also added some insulation around and above the cover for good measure.

I guess I am the only one that understands Janet's question. HEAT. I think she wants to know about the thing heating up the Metal/Alum box and/or the Insulation, once it's covered, because of OLDER bulbs being used and gets hotter while running them than these newer low wattage types. Yeah, R factor deals with Insulation(per inch protection). I didn't see the max temperature these things can endure. Seen a YT Vid that said (Rockwell) same type, is good for 2,000 degrees F. Don't know about that. Maybe she meant the "retention of heat ". If I'm wrong sorry.

Helo Okie, Yes - these are non-burnable material and will provide an air gap between the fixture and insulation cover. The mineral wool is actual a by-product on steel slag and will not burn and is one of the best insulators out there. Jeff

Assuming that the light fixture is only LED.

The item states that the it was not meant for incandescent bulbs. Yes, the heat buildup is very high with these types of bulbs. As you already know, those light cans warn the user not to cover the unit with insulation if these types of bulbs are to be used. If you are determined to use this product, you can cut holes easily into the product, but I would suggest that you get a IR temperature measuring device and do a product test.

check the spec online

This is an insulation barrier to keep air flow / transfer from house / attic through the light fixture, so it can likely be cut to fit as needed. You just need to ensure that no matter what you do, you maintain an air seal or the intended performance won't be achieved. Safety can only be determined by knowing the wattage of the bulbs you have in each fixture and the kind of heat it will generate. If you are using low wattage bulbs or LED lighting you should be fine. Otherwise, consult a certified electrician.