Recessed light

A recessed light or downlight (also pot light in Canadian English, sometimes can light (for canister light) in American English) is a light fixture that is installed into a hollow opening in a ceiling. When installed it appears to have light shining from a hole in the ceiling, concentrating the light in a downward direction as a broad floodlight or narrow spotlight.

"Pot light" or "canister light" implies the hole is circular and the lighting fixture is cylindrical, like a pot or canister.

There are three parts to a recessed lighting fixture: housing, trim and bulb. The trim is the visible portion of the light. It is the insert that is seen when looking up into the fixture, and also includes the thin lining around the edge of the light. The housing is the fixture itself that is installed inside the ceiling and contains the lamp holder. There are many different types of bulbs that can be inserted into recessed lighting fixtures, with the amount of heat generated by the bulb being a unique consideration.

The earliest recessed lights were developed in the 1940s by Ivan Kirlin of the Kirlin Company, Detroit, Michigan.

Recessed lighting offers the advantages of being a hidden light source and energy efficiency^{[citation needed]}. However, the tradeoff is that they are relatively permanent and may be unflattering.

In North America, UL 1598 recessed housings generally fall into one of four categories.

The main feature of the housing is designed to ensure that no flammable materials come into contact with the hot lighting fixture. Badly-housed downlights can be a fire hazard, though all newer ones contain a self-resetting thermal switch for safety.

The housings come in various sizes based on the diameter of the circular opening where the lamp is installed. The most commonly used sizes are 4, 5 and 6  inches in diameter, with 4  inch IC New Construction units less readily available at present. Smaller housings (2 and 3  inch) are also available for specialized uses.