HOME

TheInfoList



OR:

A recessed light or downlight (also pot light in
Canadian English Canadian English (CanE, CE, en-CA) encompasses the varieties of English native to Canada. According to the 2016 census, English was the first language of 19.4 million Canadians or 58.1% of the total population; the remainder spoke French ( ...
, sometimes can light (for canister light) in
American English American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken lan ...
) is a
light fixture A light fixture (US English), light fitting (UK English), or luminaire is an electrical device containing an electric lamp that provides illumination. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets fo ...
that is installed into a hollow opening in a
ceiling A ceiling is an overhead interior surface that covers the upper limits of a room. It is not generally considered a structural element, but a finished surface concealing the underside of the roof structure or the floor of a story above. Ceilings ...
. 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 A floodlight is a broad-beamed, high-intensity artificial light. They are often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions. More focused kinds are often used as a stage ...
or narrow
spotlight Spotlight or spot light may refer to: Lighting * Spot lights, automotive auxiliary lamps * Spotlight (theatre lighting) * Spotlight, a searchlight * Stage lighting instrument, stage lighting instruments, of several types Art, entertainment, an ...
. "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.


History

The earliest recessed lights were developed in the 1940s by Ivan Kirlin of the Kirlin Company,
Detroit, Michigan Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at ...
.


Advantages

Recessed lighting offers the advantages of being a hidden light source and
energy efficiency Energy efficiency may refer to: * Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process ** Electrical efficiency, useful power output per electrical power consumed ** Mechanical efficiency, a ra ...
. However, the tradeoff is that they are relatively permanent and may be unflattering.


Types of housing

In
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, UL 1598 recessed housings generally fall into one of four categories. #IC or “
insulation Insulation may refer to: Thermal * Thermal insulation, use of materials to reduce rates of heat transfer ** List of insulation materials ** Building insulation, thermal insulation added to buildings for comfort and energy efficiency *** Insulated ...
contact” rated new construction housings are attached to the ceiling supports before the ceiling surface is installed. If the area above the ceiling is accessible these fixtures may also be installed from within the attic space. IC housings must be installed wherever insulation will be in direct contact with the housing. #Non-IC rated new construction housings are used in the same situations as the IC rated new construction housings, only they require that there be no contact with insulation and at least spacing from insulation. These housings are typically rated up to 150 watts. #IC rated remodel housings are used in existing ceilings where insulation will be present and in contact with the fixture. #Non-IC rated remodel housings are used for existing ceilings where, ideally, no insulation is present. However, these also require that there be no contact with insulation and at least spacing from insulation. Sloped-ceiling housings are available for both insulated and non-insulated ceilings that are
vaulted In architecture, a vault (French ''voûte'', from Italian ''volta'') is a self-supporting arched form, usually of stone or brick, serving to cover a space with a ceiling or roof. As in building an arch, a temporary support is needed while ring ...
. 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. The housing can also be "Air Tight", which means it will not allow air to escape into the ceiling or attic, thus reducing both heating and cooling costs. The City of Chicago has an additional requirement "Chicago Plenum" which requires the housing to be airtight in addition to requiring all wiring and to be sealed off and gasketed from the plenum air space. This housing rating must be used on all recessed luminaires installed in air plenums in the City of Chicago as well as nearby municipalities which have adopted the Chicago amendments to the
NEC is a Japanese multinational information technology and electronics corporation, headquartered in Minato, Tokyo. The company was known as the Nippon Electric Company, Limited, before rebranding in 1983 as NEC. It provides IT and network soluti ...
. The intent of this rating is to prevent potential sparks from escaping the luminaire into the air plenum and getting recirculated in the HVAC system.
IEC The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and r ...
60598 has two classifications. #Luminaires for recessing into ceilings with thermal insulating matting covering the luminaire. #Luminaires for recessing into ceilings but not suitable for covering with thermal insulating material.


Trim styles

Recessed lighting styles have evolved with more manufacturers creating quality trims for a variety of applications. Recessed lighting trim usually comes in the standard baffle in black or white, which is the most popular. They are made to absorb extra light and create a crisp architectural appearance. There are cone trims which produce a low-brightness
aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An opt ...
. Multipliers are offered which are designed to control the omnidirectional light from "A" style
incandescent light bulb An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated until it glows. The filament is enclosed in a glass bulb with a vacuum or inert gas to protect the filament from oxida ...
s and
compact fluorescent A compact fluorescent lamp (CFL), also called compact fluorescent light, energy-saving light and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent light bulb; some types fit into light fixtures designed for inca ...
s. Lens trim is designed to provide a diffused light and protect the lamp. Lensed trims are normally found in wet locations. The luminous trims combine the diffused quality of lensed trim but with an open downlight component. Adjustable trim allows for the adjustment of the light whether it is
eyeball Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conve ...
style, which protrudes from the trim or
gimbal ring A gimbal is a pivoted support that permits rotation of an object about an axis. A set of three gimbals, one mounted on the other with orthogonal pivot axes, may be used to allow an object mounted on the innermost gimbal to remain independent of ...
style, which adjusts inside the recess. These lights allow for full versatility. Lastly, there are the wall-washer trims, which are designed to eliminate the often seen "scalloped light effect".


Bulb types

There are two types of bulbs for recessed lighting: directional and diffuse. Directional lamps (R, BR, PAR, MR) contain reflectors that direct and control the light. Diffuse lamps (A, S, PS, G) control light distribution through their omnidirectional light.


References

{{Artificial light sources Light fixtures