By Gene and Katie Hamilton
A carpenter, roofer or window installer can install a tubular skylight in about a half-day, depending on the type of obstructions between roof and ceiling, or whether reframing is necessary. If you think you need a professional to do this job, some manufacturers have networks of installers who may be able to help. If you purchase the unit online at a manufacturer's website or at a lumber yard or home center, ask if they have a "Do It For Me" installation service.
Tubular skylights are available from 10 to 22 inches in diameter. The smaller sizes fit between standard 14 1/2-in. framing openings (16-in. on-center), but the larger units need framing spaced 24-in. on-center -- or you'll have to reframe the openings to suit. Some manufacturers offer only flat interior ceiling diffusers (like many built-in fluorescent fixtures), which concentrate their illumination directly below the unit. Other models have diffusers that curve downward from the ceiling like incandescent light fixtures, and this helps to spread more light into the room.
Manufacturers claim that a 14-in.-diameter unit provides enough natural light for a 250-square-foot area, while a 22-in. model can illuminate a room area up to 400 sq. ft. Light kits are also available that can be installed inside the tube to provide electrical lighting through the diffuser after the sun goes down.