Homes built before the 1990s, and many built into the 2000s with builder grade aluminum frames, often still have their original single pane glass or bare aluminum window frames. A single pane of glass has no insulating air gap at all, and aluminum conducts heat and cold straight through the frame unless it has a thermal break built in. Neither problem is about a failed seal. This is the window doing exactly what its 1970s or 1980s design was built to do.
$800 to $1,500 per window installed, more for larger or custom sizesAddress soonWindows
The quick answer
Single-pane glass and bare aluminum frames are comfort and heating-bill problems: the glass loses heat fast and the metal conducts cold straight through, showing up as condensation, frost, and drafts. They're a budgeting item, not an emergency, at $800 to $1,500 per window installed, more for larger or custom sizes. Count how many windows are original, ask their age, and price a phased replacement into your offer.
You are reading the single pane and old aluminum frame windows page. Type the year the house was built and I will tell you what else tends to be true at that age, what it costs, and what to ask. One number, ten seconds.
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Why it matters
Windows, doors and skylights can account for up to about a third of a home's total heat loss, and single pane or uninsulated aluminum frames are usually the biggest single contributor to that number. In a Canadian winter these windows feel cold to stand near, they can ice up or sweat heavily on the inside of the glass (different from the between the pane fogging of a failed seal), and they push heating bills up every month you own the home. Buyers sometimes see original windows as a charming detail. The furnace bill doesn't agree.
How to spot it
Look at the frame material first. Painted or bare metal frames, often silver or bronze toned, with no visible spacer bar between two sheets of glass, are a strong sign of single glazing on an aluminum frame. Touch the glass and the frame on a cold day. If both feel genuinely cold rather than cool, that's a thermal signal, not just an old finish. Check for storm windows on the outside, an older fix that helps but doesn't replace true double glazing. Heavy condensation pooling on the inside of the glass in winter, especially on lower floors or bedrooms, often points to single pane glass rather than a plumbing or humidity problem elsewhere in the home.
What it costs
Roughly $800 to $1,500 per standard window installed with a mid range vinyl double pane unit, more for larger openings, bay windows, or premium frame materials. A whole house of a dozen or more original windows is a real five figure project, though it's one that can be phased room by room.
What to do
Budget this as a comfort and energy upgrade rather than an emergency. Count the original windows, note which rooms feel the coldest, and get a window company to quote a phased replacement plan. Some provinces and utilities offer rebates for ENERGY STAR rated replacements, worth checking before you book the work.
Education and triage, not a home inspection. Casaroo flags original single pane glass and bare aluminum frames from your photos. A window professional confirms condition and quotes the replacement. We flag; we don't inspect.
Common questions
Are original single pane windows a fault?
No, they are the window doing exactly what its 1970s design was built to do. That is the problem. Windows, doors, and skylights can account for up to a third of a home's heat loss, and single glazing on an uninsulated aluminum frame is usually the biggest contributor.
Can I replace them a few at a time?
Yes, and phasing is often the right call. Pricing runs $800 to $1,500 per window installed, so a full house of a dozen or more is a real five-figure project, but you can start with the coldest rooms and work through it.
Do storm windows count as double glazing?
No. They help, and they were the standard older fix, but they are not the same as a modern sealed double-pane unit and they do not change the thermal performance of the frame.
Are there rebates for replacing them?
Some provinces and utilities offer rebates for ENERGY STAR rated replacements. Check what is currently running before you book the work, because the programs change and the money is worth having.
Casaroo flags, it does not inspect. Confirm scope and pricing with a licensed window professional.
Last reviewed 2026-07-09.
This guide is general education, not a home inspection and not advice for your specific property. Always
consult the appropriate licensed professional, and get a licensed home inspection before you remove conditions
or buy. Cost ranges are 2026 estimates that vary by region, size, and access; confirm specifics with a
qualified professional.