Clerestory windows are a row of windows set high on a wall, above eye level, that let daylight pour into a room without giving up privacy or wall space below. They suit rooms with tall or vaulted ceilings and are often fixed or awning-style for easy operation. Homeowners choose them to brighten a space while keeping the lower walls free for furniture and storage.
Key Takeaways
- Clerestory windows sit above standard eye level, usually near the ceiling or under a roofline, so they light a room without exposing it to the street.
- They work best in homes with vaulted, cathedral, or split-level ceilings where there’s extra wall height to fill.
- TotalSeal builds clerestory-style units as fixed picture windows or awning windows, both available in triple glazing for U-factors as low as 1.0 to 1.3 W/m²K, well ahead of typical double glazing.
- A window must reach a maximum U-factor of 0.21 and a minimum Energy Rating of 34 to earn ENERGY STAR™ certified status in Canada.
- Expect to pay roughly the same per unit as a comparable fixed or awning window, with labour rising a bit for the height and any custom framing involved.
What Are Clerestory Windows?
A clerestory window is a narrow band of glazing installed high on an exterior wall, typically near the ceiling line or under a sloped roof. The name comes from old church architecture, where a “clear storey” of glass ran above the main walls to light the nave. In a modern GTA home, the same idea works in a living room, stairwell, or home office with a tall ceiling.
These windows are almost always fixed (picture) units that don’t open, or awning windows that tilt outward from the top for a bit of airflow. Because they sit too high to reach easily, most homeowners skip anything with a crank you’d need a ladder to use every day. A fixed or awning build also seals tighter, which matters more the higher a window sits above the living space.
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How Do Clerestory Windows Perform in Canadian Winters?
A well-built clerestory window performs the same as any other quality fixed or awning window: it depends on the frame, the glazing, and the seal, not the height it’s mounted at. Triple glazing, warm-edge spacers, and Low-E coatings all matter just as much near the ceiling as they do at floor level.
Heat rises, so a clerestory window sits in the warmest air in the room during winter, which can mean more heat loss through the glass if the unit isn’t rated well. This is where the frame build carries real weight. TotalSeal’s multi-chamber vinyl frames, paired with argon gas fills, improve glazing efficiency by roughly 25 to 30% compared with an unfilled unit. Warm-edge hybrid spacers also cut condensation risk by up to about 25% compared with older aluminium spacers, which matters on a window that’s often above a stairwell or vaulted ceiling where moisture can collect.
“A clerestory opening is still just a window in terms of physics, so we spec it the same way we would a picture window at eye level: triple glazing, a warm-edge spacer, and the right Low-E coating for the room’s orientation,” says a senior product engineer at TotalSeal. “Get those three right and the height stops being a weak point.”
Look for ENERGY STAR™ certification when you’re comparing quotes. It’s a national programme run through Natural Resources Canada, and the threshold filters out weaker builds before you ever compare brands.
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Frame Materials and Options Compared
The frame does most of the work of keeping heat in and moisture out, so it’s worth comparing before you compare glass packages.
| Frame material | Insulation | Maintenance | Typical lifespan | Relative cost |
| Vinyl (uPVC) | Very good, multi-chamber design | Low, no painting or sealing | 25 to 30 years plus | Lower |
| Wood | Good, but prone to swelling | High, needs regular finishing | 15 to 20 years without upkeep | Higher |
| Fibreglass | Very good, stable in heat and cold | Low to moderate | 30 years plus | Higher |
| Aluminium | Poor without thermal break | Low | 20 to 25 years | Moderate |
Vinyl frames tend to suit GTA homes best because they don’t expand and contract as much through our wide temperature swings, and they don’t need the yearly upkeep that wood does. TotalSeal’s frames use fusion-welded corners, which hold their seal through decades of freeze-thaw cycling rather than relying on mechanical fasteners that can loosen over time.
Glazing and Glass Options
Double glazing has two panes of glass with a sealed air or gas gap between them; triple glazing adds a third pane and a second gap for extra insulation. For a clerestory window, where you can’t easily open it to clear condensation, the tighter seal of triple glazing is worth the upgrade.
Low-E, short for low-emissivity, is a microscopically thin metallic coating on the glass that reflects infrared heat back into the room in winter and out in summer, without blocking visible light. TotalSeal’s Low-E 272 and Low-E 366 coatings are chosen by which way the window faces and how much winter sun it should let through. An optional interior i89 coating can cut heat loss by an estimated 10 to 15% on top of that.
Pros of triple glazing
- Lower U-factor, so less heat escapes through the glass
- Better sound dampening, useful near busy GTA streets
- Reduced condensation risk on cold mornings
Cons of triple glazing
- Roughly a 20 to 30% price premium over double glazing
- Slightly heavier sash, a factor on large clerestory units
Pros and Cons of Clerestory Windows
Weighing the trade-offs before you commit saves a redesign later.
Pros
- Fills a room with daylight without sacrificing privacy
- Frees up wall space below for furniture, art, or shelving
- Suits vaulted and cathedral ceilings that would otherwise sit dark
- Adds a distinct architectural look to an addition or renovation
Cons
- Hard to reach for cleaning or hardware repairs
- Limited or no ventilation if you choose a fixed unit
- Not practical in a room with a standard flat ceiling
Which Homes and Rooms Suit Clerestory Windows?
Clerestory windows suit homes with extra wall height to work with, mainly vaulted, cathedral, or split-level ceilings. They’re a strong fit for a great room addition, a stairwell that runs up two storeys, or a home office tucked under a sloped roof.
In a bungalow with a vaulted living room, a run of clerestory windows along the peak can light the whole space without a single extra floor lamp. In a semi-detached home where the side yard sits close to a neighbour’s, putting the glazing high on the wall solves the privacy problem that a standard picture window would create at that spacing. Bathrooms and ensuites also do well with a small clerestory unit, since it lets light in without anyone needing a curtain.
A standard eight or nine-foot ceiling usually doesn’t leave enough room above a door or standard window head height to make a clerestory band worth the framing. That’s a detail worth raising during your free in-home consultation, since it changes the layout the installer will recommend. Our customer reviews page has real examples of GTA homeowners who worked through this exact question with our team.
What Do Clerestory Windows Cost in the GTA?
Clerestory windows are usually priced the same as a comparable fixed picture window or awning window of the same size, since the glazing and frame are what drive the cost, not the mounting height. Expect labour to run a little higher where scaffolding or extra bracing is needed to reach the opening safely.
| Configuration | Typical price range (CAD, installed) | Notes |
| Small fixed clerestory unit | $650 to $900 | Similar to a standard picture window this size |
| Awning-style clerestory unit | $700 to $980 | Adds a hinge and hardware over a fixed unit |
| Triple-glazed upgrade | Add 20 to 30% | Worth it for the extra insulation up high |
| Multi-unit clerestory run | Priced per unit | Best value quoted as a full project |
These figures line up with what homeowners across Ontario typically pay for comparable picture and awning windows, though every home’s framing and access needs its own quote. A free consultation and our online cost estimator both give you a real number before you commit to anything.
“The height is the part people underestimate,” says a lead installation manager at TotalSeal. “We’re not just setting a window, we’re often working off a ladder or scaffold, and we have to flash and seal that opening just as carefully as one at ground level, or you’ll see a leak show up two winters later.”
How to Choose and Buy
Start by measuring the wall height available above your existing window or door line, since that tells an installer how much clerestory glazing the space can realistically take. Bring a photo or rough sketch of your ceiling shape to your consultation; a vaulted or cathedral ceiling opens up more options than a flat one.
Ask any installer about frame chambers, glazing type, and how they’ll seal and flash a high opening, since that seal matters more the harder the window is to inspect later. Compare at least two quotes, and check that both include full removal of the old opening if you’re converting from a solid wall or a smaller window.
Our showroom has sample frames and glazing packages you can see and touch before deciding, and our gallery has real GTA installs if you want ideas for how a clerestory run can look in a similar home to yours.
Frequently Asked Questions
Are clerestory windows the same as transom windows?
No. Transom windows sit directly above a door or another window, while clerestory windows stand alone in the upper wall, often as a continuous band near the ceiling.
Can clerestory windows open for ventilation?
Yes, if you choose an awning-style unit, which tilts open from the top. Fixed clerestory windows don’t open at all.
Do clerestory windows need special cleaning access?
Often yes. Because they sit high on the wall, many homeowners plan for a long-handled cleaning tool or occasional professional cleaning rather than daily access.
Will clerestory windows make a room too bright or hot in summer?
Not with the right glazing. A Low-E coating tuned to the window’s orientation controls solar heat gain while still letting daylight through.
Do I need planning permission to add clerestory windows in Ontario?
Most retrofit window replacements don’t need a permit, but cutting a new opening into an existing wall may require one. Check with your municipality before work starts.
How long does installation take?
A single clerestory unit typically takes a day. A full run of units, or a project that involves cutting a new opening, can take two to three days depending on access and framing.
Are clerestory windows drafty?
Not when they’re built and sealed properly. A triple-glazed unit with a warm-edge spacer performs just as tightly as any other well-installed window in your home.
Ready to Add Clerestory Windows to Your Home?
If your home has the ceiling height for it, clerestory windows are one of the simplest ways to bring in daylight without losing privacy or wall space. Book a free in-home consultation and we’ll measure your space, walk you through frame and glazing options, and give you a straight quote before you decide on anything.
