Roof Window or Skylight? Here’s How You Decide…

A roof window or skylight are great choices, and not just for luxurious homes. They can fill the need in places that don’t get a lot of light. They are great for letting light into a large space made from an open floor plan. 

Of course, if you have a spacious attic and want to make it into a spare bedroom, skylights and roof windows let in far more light than does that tiny window in the gable end. If you live in a neighborhood in which the homes are very close together, you may not get any daylight in the windows on the sides. A roof window or skylight can solve that problem.

choose between a roof window or skylight

The details on skylights

Most people have heard of skylights, which are sometimes called roof lights. They are mainly made of large panes of glass set into a roof to allow light into the room. They can be made of clear or frosted glass. Some are made of stained glass designs used as an architectural feature.

Some are made to be opened a few inches by tilting the glass upward on one end, either with a crank or a pole. Some feature an electronic means of opening them using switches or remotes. Some even come with rain sensors to automatically close the skylight if it starts to rain when you’re not home and the skylight is open. 

Skylights can be mounted to a curb, meaning that they don’t necessarily have to have the same pitch as the roof. Those that open usually have some sort of screen installed to keep insects out.

You may have heard the term “light shaft” in connection with skylights. This refers to the area between the skylight and the ceiling of the room below. It’s usually formed with the same drywall as the rest of the room, but may be made more decorative by using a wood product such as shiplap.

skylight and roof windows brighten this kitchen

The depth of the light shaft is often dictated by the placement of the skylight on the roof and the height of the interior ceiling. For instance, a skylight placed high on the roof will have a deeper light shaft than one that is closer in height to the interior ceiling. They are typically flared a bit to allow the light coming from the skylight to spread out more throughout the room.

What you need to know about roof windows

Another option that lets in light from the sky is a roof window. These differ from skylights in that they must follow the pitch of the roof. They open by tilting on a pivot, allowing a much larger opening than does an opening skylight. Some are even open enough for a person to get through.

person coming through roof window

A word about tube windows 

These are also known as solar tubes or tubular skylights. They are usually sized in 10 and 14-inch diameter sizes to fit nicely between roofing joists 16 inches apart or more. On the top end is an acrylic cap made to be weather resistant. At the bottom of the tube inside the house, there is a round diffuser that distributes the light coming through. In between is a tube of polished sheet metal that channels the sunlight into your home.

Tube window and diagram showing anatomy

They provide a surprising amount of light. For instance, on a sunny day, a 10-inch diameter tube window gives the equivalent of three 100-watt light bulbs. They are often used in smaller rooms such as bathrooms and laundry rooms to provide free light.

Installation options

Generally, whether you decide on a roof window or skylight, you have three options to get the job done. You can do the job yourself, hire a window company that deals in skylights, or hire a roofing company or general contractor.

The DIY option

If you have carpentry skills and have had experience installing a traditional window, you probably can handle installing a skylight or roof window, especially if yours will fit nicely between rafters. Tube windows, especially, are often installed by the homeowner as long as the tube won’t interfere with the home’s wiring or require cutting more than the holes to fit in the tube. 

The window company option

When you shop for windows, you’ll probably be offered installation services, as most dealers in these items have skilled installers on staff or that they use. You’ll be assured that they know the product and have extensive experience in window installation when you purchase from that company. You also may get a better response in case something goes wrong and you need to contact the company.

Roofing company or general contractor

Any general contractor or carpenter should be able to install a skylight. A roofing company can handle this also and is especially good if the skylight is so large that a truss or rafter needs to be cut. The contractor will be able to handle the whole job, including the light shaft, even if he needs to call in some help or a sub-contractor for the drywall work or other things.

skylight installed in bedroom bathroom

C.D. Roofing & Construction has earned the gold standard in skylight installation. We use Velux for most of our product selection but we can custom order from just about anywhere to get you the product of your choice. When you’re looking for the best skylight installers in the Durham Region, we are the preferred choice!

When to use a skylight or roof window

When thinking about whether to choose a roof window or skylight, there are a few things to consider. Building codes in your area may require a certain number of windows in a home that can be used as an escape in case of fire or other emergencies. There are some roof windows that open wide enough to allow a person to get out and will help satisfy this requirement.

To count, though, there will need to be some way to get down from the roof window, such as a rope ladder or other method. You may also need some kind of building permit to have one installed unless it’s done while your home is being built. If you get one that has a power opener, you’ll almost surely need a permit for the electrical work, including an inspection.

roof windows in a bedroom

Heat is another consideration, especially in warmer climates. Homes in colder climates can benefit from the extra heat, but if you live in a warm climate, you don’t need more heat added to your home from a skylight. While a skylight that opens partially or a roof window that opens can vent hot air outward as the air rises, the sun shining through the opening may negate any benefit. Some skylights and roof windows can be fitted with blinds to keep out the sun on hot days, but not all.


 If the placement will be out of reach, you will usually need a skylight. Roof windows need to be within reach. If you have a flat roof, you definitely will want a skylight. If you want electronic controls to open the light for air, you’ll need a skylight. Roof windows don’t have that option because of the way they open. Either can be used if replacing an old bubble skylight is the aim, but a skylight will usually be the choice.

Roof window

If you will need to access the roof through the opening, some roof windows allow you to do that. Skylights that open only open a few inches and won’t give you an exit. If you’re making a room out of your attic, you’ll want a roof window.

When considering adding extra light through the roof, skylights and roof windows are an attractive alternative to add extra lighting and ventilation. Why not look into one today? Call us and let us walk you through the best options you have available.