Recessed light fixtures (often known as canister lights, can lights, or downlights) use a design in which the fixture is contained within a metal housing that fits entirely above the plane of the ceiling. Except for a thin trim around the bottom rim and sometimes a small portion of the inner reflector, no part of the light fixture extends below the ceiling line. This can offer a number of design advantages.
Anatomy of a Recessed Light Fixture
Recessed light fixtures operate the same way as standard light fixtures, with a screw-in Edison socket that accepts lightbulbs with matching threaded bases, but the rest of the fixture has a much different configuration than standard light fixtures, designed for installation above the ceiling line.
- Bar hangers: Most recessed light fixtures have two adjustable bar hangers that allow you to brace the fixture between ceiling joists to hold it firmly in place.
- Junction box: Some recessed lights come with their own junction boxes; with others, you will have to purchase a separate electrical box. Either way, this metal box, attached to a framing member in the ceiling, is where the circuit wires are connected.
- Wire cable: Most fixtures have a metal cable that contains the wire leads that are attached to the circuit wires. The cable runs from the light fixture to the junction box, protecting the wire leads.
- Metal housing: All recessed light fixtures have a housing made of thin-gauge metal that contains the reflector, socket, thermal sensor, and any other parts. This is the "can" or "canister" that gives the fixture its other common names. The housing can be anywhere from 3 inches to 9 inches in diameter.
- Thermal sensor: Attached to the inside of the canister, the thermal sensor is a safety device that senses temperature and shuts off the light fixture if heat builds up to a dangerous degree. Overheating is a major problem with recessed light fixtures, and old designs that omitted the thermal sensor occasionally started fires. Today, nearly all recessed light fixtures are equipped with thermal sensors, and if you have old-style lights without this feature, it's a good idea to replace them.
- Reflector: A white or shiny inner lining called the reflector helps direct light from the bulb down into the room. This reflector is sometimes a swiveling gimbal cone that allows light to be directed in whatever direction you want.
- Edison socket: Inside the fixture is a standard screw-in Edison socket that accepts standard incandescent, LED, or compact fluorescent bulbs. LEDs are now very common for recessed lights, since they generate considerably less heat than incandescent bulbs. Manufacturers offer special large bulbs for use in recessed lights, designed to fill the open mouth of the reflector, although some types use standard bulbs.
- Rim: Attached to the reflector with clips, the rim is a decorative trim piece that hides the joint between the ceiling drywall and the metal housing. The rim is sometimes integrated into the reflector; the whole unit is inserted up into the metal housing as the last step of installation.
When buying recessed canister lights, you may find them designated as "old work" or "new work" fixtures, indicating whether they should be used for new construction or for retrofit installation in existing ceilings.
5 Advantages of Recessed Canister Light Fixtures
Most of the advantages of recessed light fixtures involve the visual appearance:
- Fixture is not prominent: Most traditional ceiling light fixtures are highly visible, requiring that you consider their visual design as well as the function when making your choice. But recessed light fixtures usually are not very visible, making them a good choice where you want the light itself to be the design element, not the fixture hardware.
- Work well on low ceilings: Rooms with low ceilings, such as basements or attic conversions, are practically begging for recessed lights. Traditional ceiling fixtures in such rooms will either graze occupants' heads or be too visually dominating. Recessed lights allow the plane of the ceiling to remain intact.
- Can cover edges of a room: While traditional ceiling fixtures tend to provide good light in the center of a room, the edges of the room can be somewhat dim. But low-profile recessed lights can provide uniform lighting around the entire room, especially when installed in groups.
- Recessed lights can be "pointed": Some styles have moveable gimbal reflectors that allow the illumination to be directed toward specific features, such as artwork, a brickwork wall, cabinetry, or other features.
- Waterproof fixtures are available: Recessed lights are the only light fixtures that can be installed in water-intensive environments, such as shower stalls.
- Always "on-trend": Unlike track lighting, which shouts "1980s!" or monorail lighting ("2000s!"), recessed lighting is more or less trend-proof. The reason recessed lights never go out of style is that they have never really been in style.
While recessed lights do a great job of giving you a sleek, clear ceiling, there are some functional drawbacks:
- Small illumination area: By nature, recessed light fixtures are directional and cast light on a relatively small area. This is an advantage is some situations, but it means that individual lights are not very good at whole-room illumination.
- Requires multiple fixtures to fully cover a room: Traditional ceiling light fixtures cast illumination in a full 360 degrees, but recessed lights cast a narrow downward cone of light. To fully illuminate an entire room, you will need to install multiple fixtures and position them carefully. For a 15 x 20-room, for example, it may be necessary to install as many as 12 recessed lights to provide full illumination.
- Not energy efficient: By design, recessed lights require fairly large holes in the ceiling drywall, and these openings can allow heat to escape upward. Heat loss in winter can cause a notable increase in energy costs. And because many recessed lights are sometimes necessary to fully illuminate a room, they can produce a considerable amount of heat, leading to increased cooling costs in the summer. To remedy these issues, consult EnergyStar for advice. Some states, such as California (Title 24) have strict regulations on this, requiring either air-tight recessed lights or that the installer covers the light with insulation.
- Some styles are not compatible with insulation: Some types of recessed light fixtures can generate a dangerous amount of heat if they are covered with insulation. You must make sure to buy fixtures appropriate for the type of installation you have.
Recessed Light Fixtures and Ceiling Insulation
During the first energy crisis of the 1970s, homeowners began adding thick layers of insulation to their attics to conserve energy. Some people then found that covering them with insulation caused the fixtures to overheat, sometimes to a degree that caused home fires. Several solutions were quickly developed. Builders learned that enclosing the canister in a plywood box to keep insulation from directly contacting the fixture could prevent it from overheating. Light fixture manufacturers also began equipping recessed light fixtures with thermal sensors that automatically shut off the fixture if the heat built up to a dangerous temperature.
Recessed light fixtures are commonly designated as "IC" (insulation contact) or "no IC" (no insulation contact) to indicate if they can safely be installed with insulation directly touching the canister.
Ideally, your fixtures should have both features: box enclosures to keep attic insulation slightly away from the fixture and recessed lights with built-in thermal sensors. But in old installations, you may find that neither feature is present. If so, it's a good idea to replace the fixtures with modern ones. This is generally a fairly easy DIY project.
Wiring for Recessed Light Fixtures
Recessed light fixtures are wired in much the same way as standard light fixtures, with a black wire lead that connects to a black (hot) circuit wire), and a white lead that connects to a white (neutral) circuit wire. A green grounding lead is connected to the circuit's bare copper grounding wire.
These circuit wires are controlled by a standard wall switch or dimmer. If you are replacing a standard ceiling light fixture with a recessed canister light, the same wall switch can control the new fixture. The only difference is that canister lights are very often installed in groups so that additional lengths of circuit cable are looped down the line from the first fixture to subsequent fixtures. There is nothing unusual about this, and any electrician or experienced DIYer can easily complete this cable routing and these connections.
Recessed canister light fixtures can be installed anywhere a standard ceiling light fixture is used, but there are some typical applications where they are most often found:
- Home movie theaters: Theaters benefit from the clear sight-lines that recessed lights provide.
- Kitchen perimeter/above counters: Since recessed lights are directional, they work well as kitchen task lights to direct light down onto countertops, or to cast light across the face of kitchen cabinets.
- Kitchen islands: Task lighting provided by recessed light fixtures can brighten a kitchen island while keeping the center of the room clear of ceiling obstructions.
- Showers stalls: When equipped with watertight lenses these lights can get splashed with water without danger.