Acoustic ceilings, or drop ceilings, are the ones you see in many businesses, where the ceiling looks like a grid with movable panels that lift up and out. These ceilings are occasionally used in homes, too, but this raises more than a few questions as people try to combine the lightweight, movable panels with common home fixtures, such as recessed lighting. It is possible to use recessed lighting in a drop ceiling if you follow a few rules.
Recessed light cans are obviously much smaller than the panels in a drop ceiling, and the panels are not strong enough to hold the lights themselves. The answer, notes the Armstrong company, is an additional frame that rests on the ceiling grid. The frame has two bars that rest across two opposite sides of a grid square, and extra hanging wires are attached between the grid beam and the interior ceiling that's holding up the grid, to provide extra strength to the entire structure.
The frame can sit anywhere under ceiling as long as it provides enough steadiness and strength to prevent the light from falling or cracking the panel. While many examples of recessed lighting in drop ceilings show the lights in the center of the panel, this is for aesthetic purposes. Recessed lights can also sit along the side of the panel, closer to the ceiling grid.
Heat From the Lights
Recessed lighting can get hot, and you have to use specially rated cans that are meant for indoor residential use. An additional concern with drop ceiling panels is that some of them are made from materials like fiberglass, which have a plastic coating that can melt if placed next to a hot light. Incandescent lights are the main culprit, although anything that makes the light cans hot is a risk. If the panels in the drop ceiling have this plastic coating, do not install recessed lighting that uses lights that give off a lot of heat, especially those that use incandescent bulbs. If you do not know what materials are in the panels, contact a company that specializes in drop-panel ceilings and see if they can tell you.
All recessed lights will have specific manufacturer instructions in terms of placement, hanging, fire rating and heat exposure, and bulb use. Always follow these instructions for the exact light. Don't assume that because you used a certain type of recessed lighting before that it will be just fine in a drop ceiling. The additional fire risk from the materials, not to mention the weight of the cans and lights versus the strength of the frame, is not something to ignore. Also check local building and housing codes regarding recessed lighting.