The honest answer to “what does a window cost” is that it depends on the opening, and nobody who has not measured the house can give you a number that holds. What we can do is show you where the money goes, what a typical Scarborough or Markham job looks like, and what published price ranges in the GTA say, so the quote you get makes sense when it arrives.
Reviewed by Steve McCue and Steve Mercer, owners, Fortress Windows & Doors Inc. Updated September 16, 2026.
Published ranges for the GTA
HomeStars’ contractor guide for Markham lists standard vinyl window replacement at $300 to $800 per window including installation, and energy-efficient or triple-pane windows at $600 to $1,200 per window. Those are aggregated figures across many contractors and window sizes, not Fortress prices, and the low end of that range is usually a small, fixed unit on the ground floor. A large casement over a kitchen sink, or a second-storey window that needs a ladder and two people, sits toward the top.
Our own quotes come as one written price per job after Steve Mercer has measured every opening. That price includes the window, the glass package, removal of the old unit, installation by our own crew and the True Fortress Exclusive Lifetime Warranty on parts and labour. There is no second number after the old window comes out.
What actually moves the price
Size and how many
Bigger glass costs more, and so do more openings. But per-window cost drops on a whole-house job because the crew is set up once, the measure is one visit and the order ships together. Replacing ten windows at once is nearly always cheaper per window than doing three this year and seven the next.
Style
A fixed picture window is the cheapest way to fill an opening. Casements and awnings have crank hardware and multi-point locks, so they cost more than a slider or a hung window of the same size. Bay and bow windows are a different job altogether: the unit projects off the wall and has to be supported, roofed, flashed and insulated, so it is priced as a small construction project, not as three windows.
Glass
Every window we install comes with Low-E 272 glass and argon fill, which is what earns the ENERGY STAR certification. Triple-pane glass costs more per unit. It makes sense on a north-facing bedroom on a busy road, where you want the noise reduction as much as the insulation. It is rarely worth it on a small south-facing window.
What is behind the old frame
This is the one no online calculator can see. Old wood frames in Scarborough bungalows from the 1950s and 60s often have rot at the sill from decades of condensation. Aluminum sliders from the 70s and 80s in Markham and Pickering leave a frame that is sound but out of square. Either one adds labour, and Steve Mercer’s background as a home inspector is why he pokes at the sill during the measure instead of finding out on install day.
Access
A second-storey window over a sloped porch roof takes longer than the same window at grade. So does a basement window that is being enlarged for egress, which involves cutting the foundation and is quoted separately.
Count and condition
Two houses with ten openings each can price very differently. A 1980s two-storey in Ajax with sound framing, mostly casements and a couple of basement sliders, is a straight replacement. A 1960s Scarborough bungalow with eight openings and rot at three sills needs repair before anything new goes in. The number of openings is half the story; the condition of what is behind them is the other half, and only a measure visit finds it.
For a look at a whole-house job, every window, the entry door, the patio door and a garage door, see the Oro-Medonte project.
The rebate and financing
Ontario’s Home Renovation Savings program pays $100 per rough opening on ENERGY STAR windows and doors, but only if you complete a home energy assessment and pair the windows with a second upgrade type. On ten windows that is $1,000 back, plus a $600 assessment rebate. The rules, the December 31, 2026 cut-off and what has closed are in our Ontario window rebates guide.
Financing is available on Fortress installs if you would rather spread the cost. Ask when you book the measure.
Getting a number you can trust
Ask for the quote in writing, with the window style, the glass package and the ENERGY STAR model numbers on it. Ask who installs: a subcontracted crew is where most of the horror stories come from. And ask what the warranty covers. Most cover the part and bill you for the visit; ours covers both.
Call (416) 291-5795 in Toronto and Durham or (705) 294-2345 for Barrie and Simcoe County. The measure is free and the price is one number.
Frequently asked questions
How much does it cost to replace windows in Toronto?
Published GTA ranges put standard vinyl replacement windows at roughly $300 to $800 per window installed, and energy-efficient or triple-pane units at $600 to $1,200. The real number depends on size, style, glass and the condition of the opening, which is why a written quote after an in-home measure is the only figure worth relying on.
Is it cheaper to replace all the windows at once?
Per window, yes. One measure visit, one order and one crew set-up spread across ten openings costs less than three separate jobs, and a full-house job is what the Ontario rebate’s minimum of three openings and two upgrade types is built around.
Do I need triple-pane windows in Ontario?
Not usually. Double-pane Low-E 272 glass with argon meets ENERGY STAR and handles a GTA winter. Triple-pane is worth the extra cost on windows facing a busy road or a cold north exposure where noise and comfort matter most.
Why did my quote go up after the old window came out?
Usually because rot or an out-of-square frame was found after the fact. A proper measure checks the sill and frame before pricing so that does not happen. Fortress quotes are one written price.
