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How Long Do Windows Last in Ontario? Vinyl, Wood, Aluminum and Fibreglass, the Sealed Unit, and the Age When Each Crosses the Line
Windows & Doors
How Long Windows Really Last Here, by Material, and the Part That Fails First on All of Them
“Lifetime warranty” on a window means the lifetime of the warranty, and the warranty is written by the manufacturer. The real question is how many Ontario winters the frame, the glass seal, the hardware and the installation each get, because they are four different lifespans and the shortest one decides when you start getting quotes.
The numbers
| Window | Real life in Ontario | What goes first |
|---|---|---|
| Builder-grade vinyl, 1990s to 2010s | 20 to 25 years | Sealed units fog at 15 to 20; weatherstrip flattens; a corner weld cracks on the south side |
| Good vinyl, welded frame, multi-chamber | 30 to 35 years | Sealed units at 20 to 25; hardware |
| Fibreglass | 40 years and more | Sealed units; the frame itself barely moves |
| Wood, aluminum- or vinyl-clad | 35 to 50 years | The cladding joint at the sill, if water gets behind it |
| Wood, painted, with storms | 60 to 100 years, with paint | Rot at the sill and lower rails when the paint is let go |
| Aluminum, 1950s to 1970s, no thermal break | Done | Ice on the inside of the frame; they were never insulated |
| Sealed glass unit, any frame | 15 to 25 years | The seal, then the argon, then the fog |
| Casement operator and hinges | 15 to 20 years | Gears strip; arms bend; parts for old series disappear |
The sealed unit is the clock!
Every double- or triple-glazed window has an insulated glass unit: two or three panes sealed around a spacer with a desiccant inside and argon between. The seal is the weak point. Sun heats the unit, the gas expands, the seal flexes; cold shrinks it back. After 15 to 25 years of that the seal lets go, the argon leaves, moisture gets in, and one morning the window is fogged. The frame is fine. A $250 to $450 glass swap puts the window back for another 15 to 25 years. The repair page is about this more than anything else.
South and west units fail first, dark frames fail sooner, and the units in a kitchen or bathroom with no exhaust fan fail soonest of all, because they spend every winter night wet on the inside.
What shortens the life of any window
- No foam at the perimeter. Air moving around the frame carries moisture into the wall, and the frame rots from behind. The install, not the window, sets the clock here.
- Indoor humidity over 40% in January. Condensation runs down the glass onto the sill every night. Wood sills rot; vinyl sills grow mould under the stops. Condensation.
- Dark vinyl on a south wall. Vinyl softens with heat; a black south-facing frame cycles further every day than a white north one. Good laminates handle it; cheap paint does not. Black frames.
- Sprinklers and grade. A lawn sprinkler hitting a window every morning, or a basement window well with no drain, does in ten years what weather does in thirty.
- Nobody adjusting anything. Casement locks loosen, slider rollers wear, weatherstrip compresses. Ten minutes a year with a screwdriver adds five years.
The signs a window is on its last winter
- Soft wood at the sill corners, outside or in. Press with a screwdriver. If it goes in, the frame is done and it is a full-frame replacement.
- A crack at a vinyl corner weld. Usually the bottom corner on the sunny side. It will not stop there.
- Frost on the inside of the frame, not the glass. The frame has no thermal break, or the foam is gone. Either way the window is costing you every night.
- A sash that will not lock without lifting it. The frame has racked. Hardware will not fix a racked frame.
- More than one of these on more than a third of the windows. That is the house’s window clock, not one window’s, and it is time to price the package.
What the warranty actually promises
A “lifetime” vinyl warranty usually covers the frame against cracking and the sealed unit against seal failure for a set number of years (10 to 20 is common), often prorated after the first few, often not transferable, and almost always excluding labour. Hardware is 1 to 10 years. Colour on dark frames has its own term. None of it covers an installation fault, which is the installer’s separate warranty and the one that actually matters in year three. The warranty page reads one line by line.
Questions people ask
How often should windows be replaced?
When they fail the tests above, not on a schedule. A good vinyl window with a fresh sealed unit at year 20 is a 35-year window. A bad install is a 10-year window whatever it cost.
Do triple-pane windows last longer?
The frame, no. The sealed unit has three panes and two seals instead of one, so there is more to fail, but the spacer technology is newer and the units are heavier, which puts more load on hinges. Call it the same, with a warmer glass surface meanwhile.
Are old wood windows worth keeping?
If they are painted and the sills are sound, yes. A rebuilt wood window with new weatherstrip and a good storm is a 60-year window and the glass can be replaced. They are more work than vinyl. They are also better looking than any vinyl made.
Before you replace them, check which part failed
The repair vs. replacement page is the test, window by window. If it is the frames, the calculator prices the package.
Sources and further reading
- Keeping the Heat In: Natural Resources Canada. The free guide to windows, doors, air sealing and insulation written for Canadian houses.
- ENERGY STAR Canada technical specification for windows, doors and skylights: Natural Resources Canada. The U-factor and Energy Rating thresholds, and the certified product lists.
