Of the 3 kinds of insulation you are likely to use in your attic, rock wool has the very best fire rating and cellulose the worst. Insulation flammability isn’t a problem using recessed lighting fixtures, however. If a fixture isn’t rated for insulation contact, no insulating material should come within 3 inches of the fixture, and any that does could smolder and catch fire. You can safely pack any insulation material about an insulating material contact, or even IC-rated, fixture, nevertheless.

The Chimney Effect

Recessed lighting fixtures give appealing ambient lighting, but installation of the canisters often creates gaps during which air may move. Warm air escapes into the attic during the winter and can be replaced by cold air coming from gaps in the foundation or poorly sealed doors and windows. This upward draft, which is similar to the movement of air in a chimney, which makes the living space harder to heat and wastes energy. To avoid this impact, it’s important to seal the gaps across each recessed lighting canister you install, but you can not stuff insulation about every kind of recessed lighting fixture.

Insulation Contact Rating

The best way to avoid losing heat during gaps around recessed lighting fixtures is to use IC-rated fixtures, which are safe to cover with insulation. They’re designed to work only with low-wattage bulbs and have a thermal protector that trips once the bulb conquers the wattage limitation. When using a non IC-rated fixture, you must keep insulation at least 3 inches apart from it, which involves construction of an insulating material dam or installation of a specially-designed cover. When utilizing non-IC rated fixtures, the type of insulation you use, and especially its fire rating, become vital.

Insulation Choices

When insulating above a ceiling using non IC-rated recessed lighting, the least flammable substance to use is rock wool, also called mineral wool or slag wool. It will not burn until the temperature reaches 1,800 degrees Fahrenheit, which can be over a recessed lighting fixture may generate. The next safest alternative is fiberglass without a paper backing — either batts or loose fill. Among its advantages are that it’s less rigid, lighter and easier to material into little areas. Loose-fill cellulose, which can be basically recycled paper treated with a flame retardant, begins smoldering at approximately 450 degrees Fahrenheit. It is the most hazardous substance to use about recessed lighting.

ICAT Fixtures

Installing Aerial Pen Air-Tight — ICAT — fixtures avoids issues with insulation flammability and reduces drafts; these fixtures are internally sealed to reduce air movement during the canisters themselves. They may safely come in contact with any insulation material — even cellulose — also since the sides of the canisters remain cool, you can caulk about them. The wattage restrictions on ICAT and IC-rated fixtures limits the amount of light they provide, and you might prefer a non-IC rated fixture when you need more lighting. Non IC-rated fixtures are best used in the lack of insulation, but when insulation is necessary, it shouldn’t be cellulose.