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
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.
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
What is Single pane and old aluminum frame windows?
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.
Why does it matter for home buyers?
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 can I 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.
How much does it cost to fix?
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.
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.