Homeowner’s Guide to Skylights

Skylights do more than brighten a room. They let in not only light, but heat, which means less hard-earned money spent on heating fuel in the winter. Some types of skylights also allow in fresh air in the summer and reduce cooling expenses. Skylights can have such a positive impact on energy consumption that, through the end of 2022, they qualify for a 26 percent federal tax credit.

Perhaps you’re considering installing skylights for the first time, or maybe you need to replace your existing skylights. Know that if you choose the right ones, they could last almost as long as your roof. Here’s what you need to know.

Fun fact: The largest skylights in the world, at the CORE Shopping Centre in downtown Calgary, Alberta, each measure 656-ft. x 85-ft. and incorporate 1,740 pieces of glass.

Types of Skylights

These are the three basic types of skylights:

Fixed

Fixed skylights don’t open. They consist of a pane of glass or sheet of plexiglass mounted in a frame. If the frame supports the glass at some distance above the roof (a minimum of four inches is recommended), it’s known as a curb.

Curb-mount skylights are easier to weatherproof than flush-mount ones that sit even with the roof decking, but they interfere with the look of the roof line. Curbs can be flared or slanted to face the sun more directly and allow more light into the room, which isn’t possible with flush-mount skylights

Ventilated

A ventilated skylight opens like a casement window. The opener may be manual (a long-handled crank) or electric. Velux manufactures a solar “Fresh Air” skylight that incorporates a solar panel to charge the crank motor battery. It comes with a sensor that automatically closes the skylight when it starts to rain.

Tubular

Tubular skylights are alternatives to fixed and ventilated skylights for homes with limited roof space or rooms underneath an attic. Available in 10-, 14-, and 21-in. diameters, dome-shaped tubular skylights connect to a reflective tube that extends from the roof to the room below. The tube contains mirrors or other optical techniques to take as much advantage of available sunlight as possible.

Materials and Accessories

Skylight panels can be made from glass or plexiglass. Glass has better insulation value and won’t fade or yellow, but it’s more expensive than plastic. Plastic is easier to mold into dome shapes that shed water better than flat panels and allow in more light. But plastic is more prone to clouding and cracking and usually needs to be replaced sooner than glass.

Welcome light in the winter can make a room uncomfortably hot in the summer, so manufacturers also supply skylight shades. These vary in opacity from translucent to complete blackout. Mounted inside the room, they can be operated manually or with a remote control or smartphone. If you skylights didn’t come with shades, you can order them from third-party suppliers.

Skylights also can be coated with semi-reflective tinting material to reduce glare and heat transmission. While it’s easier to do before installation, you can apply window tinting film to most flat skylights afterward. Films won’t work for dome-shaped skylights, but you can cover them with sun-blocking solar mesh.

Tips for Choosing a Skylight

Factors to consider when choosing a skylight:

• Roof structure: A skylight that fits between the roof rafters is the easiest to install. Many are sized in standard 24-in. spacing. If you need a bigger skylight, the installation will take longer and cost more.
• Roof slope: A domed or pyramid-shaped skylight sheds water better than a flat one. It’s better for a flat roof or one with a gentle slope.
• Visibility: A flush-mount skylight that follows the roof line won’t disrupt the appearance of the house as much as a curbed one that rises above the roof line.
• Ceiling height: Electric or fixed skylights are better choices for ceilings too high to reach with a manual crank.
• Attic: Neither a fixed nor ventilated skylight will work in a room below an attic. Better to install one or more tubular skylights.
• Cost: A skylight with all the extras, such as the Velux Fresh Air model, can cost $2,800 with installation before you apply any tax credit. Tubular skylights are the cheapest to install, around $750 each. Go with professional installation if you don’t feel comfortable working on your roof.