To evenly distribute or concentrate lighting in a room, homeowners can opt to install recessed lights in ceilings. Factors ranging from lighting direction and room function to the design of the housing unit will determine the minimum distance between each lighting fixture. Before installing the lights, temporarily wire and hold up fixtures against the ceiling to observe whether the spacing produces the desired effect in the room.
Decide what function or purpose you want recessed lighting to serve for the room. The placement of recessed lights in kitchens will be different from the placement of recessed lights in dens or family rooms. For example, most kitchen tasks are performed at counters or over islands where strong lighting is desirable. If you are using recessed lighting to illuminate only certain sections of a room or decorative elements, then this will also influence the minimum distance units should be spaced apart.
Down lights beam straight down in a cone-like shape. Because the diameter of light projected from the cone is directly related to the ceiling's height, the spacing between down lights should equal no more than 75 percent to 95 percent of the ceiling height, according to a Lowe's article on lighting installation. For example, if the ceiling height is 8 feet, then the distance between cans should be 6 feet to 7 feet, 6 inches apart.
According to the Lighting Research Center, the recessed lighting unit's design, distance from the wall and spacing will affect the lighting's effect on the room. For instance, some wash lights fade toward the bottom of the wall, while other wash lights diffuse light or hide internal reflectors from view. To prevent mirror images from appearing on polished wood or marble surfaces, install wash wall lights a minimum of 2 1/2 inches from where the wall meets the ceiling. Position the cans so that light shines away from doors and windows, and not directly at passersby.
In addition to proper spacing across the square area of the ceiling, recessed lighting must be installed at a certain depth in ceilings to operate effectively. According to the Lighting Research Center, most housing units or cans need to recede at least 8 inches into the ceiling. These installation requirements restrict the types of ceilings that can use recessed lighting because of the spacing needed for insulating materials. Recessed lighting covered with thermal insulation must have an insulated ceiling rating. Moreover, IC-rated recessed lights meet building code requirements intended to minimize air leaks through recessed lighting fixtures.