You can add skylights to an existing roof, but they will work best on angled roofs to ensure water can run off the roof. You’ll also want to hire a contractor with experience retrofitting skylights into roofs, as an improperly placed skylight may leak in the future.
Most skylights last between 20 and 40 years, although others can last up to 55 years. The life expectancy of a skylight depends on the brand you choose, the quality of the installation, and the climate. Areas with changing temperatures and lots of rain may see more frequent damage. Be sure to choose a window with a warranty in case the skylight leaks or fails before its expected lifespan is over.
Tubular skylights—also known as tunnels, tube lighting, or solar tubes—have been around since the 1980s. They’re small, cylindrical-shaped windows with a dome that sits on the roof, typically in small rooms, hallways, and closets. Solar tubes diffuse light into a home and filter out UV rays, but they don’t offer a view of the sky. In comparison, skylight windows offer sky views, and some contain filters that partially block harmful UV rays.
Skylights are usually more expensive and challenging to install than solar tube lighting. A tubular skylight costs between $450 and $1,300 for the product and installation. That's about 60% of the price of a skylight or a roof window because the opening is smaller than fixed styles.