How Many Recessed Lighting Cans Are Recommended Per Square Foot

Recessed accent lights can highlight special objects.

Many homeowners favor recessed lighting in modern homes and remodels because they take up no visual or actual space, adding a clean appearance to any room. Calculating the number of lights you need is important, however, since they cannot easily be moved to new locations. Electrical connections and ceiling insulation can also affect lighting placement.

General

To determine coverage in square feet with general lighting, the basic rule is to multiply the mounting height in feet by four. For example, a single downlight on a 10-foot-high ceiling can cover about 40 square feet of space on the floor. A small 5-by-8-foot closet would need just one recessed light, while a 10-by-12-foot room (120 square feet) would require three units. To determine spacing, draw out the coverage on a room plan and put the light in the center of the coverage. General lighting typically uses baffle or reflector styles.

Task

Task lighting focuses the beam in areas where light is needed most, such as on a kitchen countertop or desktop. It typically requires twice the light in general use areas and uses reflector styles. To calculate task lighting using a lamp with a 30 degree beam spread, first subtract the height of the surface from the ceiling height. For example, a 10-foot ceiling minus a 3-foot-high table equals seven. Then multiply the difference by three. In this case, seven multiplied by three equals 21 square feet of lighting coverage over the surface. Use as many lights as needed to cover just the work areas and not the areas where people stand or sit.

Accents

Accent lighting highlights room features such as a painting, sculpture or wall niche, creating drama in a space. Use as many recessed lighting cans as you have objects you want to emphasize. Assuming a 30-foot beam of light provided by directional balls, measure the distance between the ceiling and the center of the object. Then divide the result by two and multiply it by 1.1. For example, if the middle of a picture is 36 inches from the ceiling, then half of 36 equals 18. Multiplying 18 by 1.1 gives you approximately 20 inches. The recessed light should be installed about 20 inches from the picture wall.

Obstructions

Ceiling construction can affect the number and placement of recessed lighting cans. Use a studfinder or knock on the ceiling to locate the studs, because lights can only be installed next to, or in the spaces between studs. Watch out for vents near or at the ceiling because air ducts leading to those vents can obstruct installation. Be careful at corners and along exterior walls where the roof can join the ceiling. Roof trusses and beams can interfere with any units. It's a good idea to crawl into the attic and inspect any potential obstructions before cutting holes in the ceiling for lighting cans.

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