Recessed lighting is a popular feature in both new construction and in remodeled homes, but an important safety factor is not obvious. Some recessed light fixtures are designed to be safe for insulation contact and are designated IC-rated. Non-IC-rated fixtures require clearance from all combustibles, typically three inches. These non-rated fixtures can cause fires if installed in contact with insulation.
Fixtures that are not rated for insulation contact have a single walled canister, which can grow quite hot from the heat of the bulb. This heat is designed to dissipate into the empty space that the recessed fixture is installed within. If insulation covers the canister, it can cause the fixture to overheat and potentially start a fire. If combustible insulation is in contact with the canister, it can heat up and ignite. Modern fixtures have a heat-sensitive internal switch that can shut off the circuit if the fixture overheats.
What makes a light fixture safe for insulation contact is a two-walled design. While the inner canister can grow hot, the heat dissipates in the chamber formed by the outer canister wall. This outer wall should remain cool enough to be in contact with and covered by insulation.
The low-profile appearance of most recessed lighting gives few clues about its IC-rating status from the living space. Non-IC-rated lighting can be found in both remodels and in new constructions. They are appropriate for ceiling applications where insulation is not present above the ceiling. If installed in an insulated attic space, they should be equipped with baffles or shrouds that prevent insulation from close contact. Insulation tends to get moved around in attics from installation and maintenance activities, and it is not uncommon to find insulation fibers inside shrouds designed to keep them out.
Keeping insulation away from recessed lighting with shrouds poses another problem: heating or cooling loss. Uninsulated area in the attic around a light fixture will allow heat transfer between the conditioned living space and the attic. Not only does this reduce the energy efficiency of the home, heat in unconditioned attic space increases the chances of mold growth. Warm air holds more moisture than cold air, so if attic air is heated from uninsulated ceilings, the air tends to become more humid. When humid air meets the cold lower surface of roof sheathing, it may condense on this surface. Since mold spores are everywhere in the air and filter into attics through ventilation openings, moist surfaces foster spores germinating and fungal hyphae growth.
A better solution is to fully insulate ceilings below attic spaces. IC-rated light fixtures are designed for this application as long as bulb are kept within the designated rating. In new construction, builders should ensure that IC-rated fixtures are installed wherever ceilings will be insulated. However, older homes typically had less insulation, so remodels may be equipped with non-IC-rated fixtures. Additional insulation may have been installed later, in some case covering the vulnerable fixtures.
One straightforward way that may reveal the rating status of a fixture is to remove the bulb. Some will clearly state whether they are IC-rated or if they require 3 inches of clearance from insulation.
The IC rating is applicable if the correct size and type of bulb is used for the fixture and the trim installed. The trim is the outer rim of the fixture, and influences how heat can escape from the canister. Trim designs that allow more heat release can allow installation of higher power bulbs. In the example shown here, the IC fixture has a chart that shows which bulbs can be used depending on the trim. With one type of trim, an incandescent bulb of only 40 watts can be used. Note that further down, if a different trim is used, a 60 watt of the same type can be used. This chart also shows that bulbs that direct more light downward can be of higher wattage.
If installing recessed lighting, a homeowner should select canisters that are rated for the insulation conditions of the space, and trim that allows the desired types and wattages of bulbs. Another consideration for new installation is whether the fixture is rated AT or air-tight. Air-tight fixtures are designed to eliminate air movement from conditioned indoor space to uninsulated spaces, typically attics. This can result in large savings in heating and cooling energy, as a small opening allowing air movement can transfer as much heat as many times that area that merely lacks insulation. Air-tight fixtures also help prevent attic air, which typically contains insulation fibers, dust and perhaps mold spores, from entering the living space.
In homes that have existing recessed lighting, homeowners should inform themselves on the IC status of the fixtures. As noted, removing the bulb may reveal labels with that information. Information not on the fixture may be found online if the manufacturer and model number are present. It is wise to inspect several fixtures, especially if they are in different rooms or look different. A home may have a mix of IC-rated and non-IC rated fixtures. It is also important to determine the bulb type and wattage rating and compare that with the fixture chart if present. Keeping in mind that bulbs wear out and are typically replaced at different times, a scan of all bulbs for excessive wattage is recommended.
If non-IC-rated fixtures are present, with insulation covering them, they could be replaced with IC fixtures to avoid removing insulation. Alternately, as a less-expensive step, they could be replaced with LED bulbs. LED bulbs have much lower wattages than incandescent bulbs for comparable light outputs and generate much less heat. They also have much longer lifespans, which can offset the investment. Following manufacturer recommendations is always the safe approach.
Recessed lighting can be a great feature in a home, and the fire risk of inappropriate fixtures makes investigating them vital. If adding recessed fixtures, research can help you direct your investment in safe ways that meet your needs. If purchasing a home with existing fixtures, inspecting them can alert you to safety concerns and potential repair needs. We hope this article can help you follow up on a thorough home inspection with your own observations.
