Spring brings the window replacement rush in the GTA. The workable season runs roughly late April through October: installers can work without cold-cure adhesive workarounds, caulking seals properly, and you are not heating a hole in your wall while the crew works. If you have been putting off replacements through the winter, now is the right time to move — and also the right time to understand what is genuinely one of the more confusing renovation quotes in residential contracting.
What you are actually buying
Every window quote has three cost layers: the unit itself, the installation labour, and the incidental work — patching interior trim, replacing rotted sill or rough-opening framing. Most quotes make the first two obvious and bundle or hide the third. On older Toronto-area housing, pre-1980 brick construction and 1970s semis especially, the incidentals category is where quotes diverge sharply from reality.
The unit cost for a mid-grade casement window in 2026 runs $350 to $700 per opening, depending on frame material (vinyl vs. fibreglass) and glass package (double vs. triple pane, low-e coating, argon fill). Premium fibreglass units from Jeld-Wen, Pella, or Marvin run $800 to $1,400. Budget vinyl from box-store brands runs $180 to $300 but typically carries shorter warranties and less consistent argon-fill retention over time.
Installation labour adds $150 to $400 per opening, depending on whether it is a retrofit (leaving the exterior casing and brick mould in place) or a full-frame removal. Retrofit is faster; full-frame is right when the rough opening has frame damage, rot, or prior water infiltration. On a lot of 1960s and 1970s GTA housing, you will not know which one you actually need until the old unit comes out.
A whole-house replacement on a standard GTA semi (8 to 12 windows) will realistically run $6,000 to $18,000 installed, depending on unit grade and what the installer finds in the rough openings.
What the Energy Star numbers actually mean
Ontario falls in Zone 2 for Energy Star certification. The current minimum for Zone 2 is a U-factor of 0.27 or lower. Most mid-grade vinyl double-pane units with argon fill and low-e glass clear this threshold without much effort. What the Energy Star label does not guarantee: the unit was tested in the configuration installed in your wall. Off-axis installation, missing rough-opening insulation, and sloppy air-sealing at the interior trim can produce real-world performance well below the lab number. The spec is for the unit in ideal conditions, not your 1962 brick wall in February.
The Ontario Home Renovation Savings Program (HRSP) offers rebates for window replacement under the Building Envelope category, currently $0.65 per square metre for improved U-factor performance. That typically works out to $80 to $200 on a whole-house job. Worth claiming, but not worth choosing a lower-quality unit to chase it.
Casement vs double-hung for Toronto homes
Casement windows (side-hinged, crank-operated) seal better than double-hung because the sash presses against the frame seal when closed. In a cold climate, that compression seal matters for draft reduction and condensation control on glass edges. Double-hung windows are easier to clean from inside (both sashes tilt) and are code-required above certain floor heights in bedrooms for egress purposes. For typical GTA bedrooms, a double-hung with a minimum opening area of 0.35 square metres and a minimum 380mm clear opening dimension meets Ontario Building Code egress requirements. Casements also meet the spec if the opening clears the same thresholds.
Permits
Replacing like-for-like windows — same size, same location — does not require a building permit in Toronto. Enlarging an opening, changing a window to a door, cutting a new opening, or changing the window type in a way that affects egress does. Most standard replacement jobs do not trigger permits. If a contractor suggests skipping a permit on a project that clearly should have one (say, cutting down a rough opening to fit a smaller stock-size unit), push back before signing anything.
Reading the quote
Before signing, check whether the quote specifies retrofit versus full-frame removal, since that distinction drives labour cost more than unit price does. Check whether it includes interior trim work and priming — a lot of quotes stop at the window itself and leave you with bare drywall returns. And ask what happens if they find rot in the rough framing. A reasonable per-opening repair rate is $200 to $400 for a single beam. If they cannot give you a number, they have not thought it through.
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