Window Repair or Replacement? How to Tell What You Are Actually Looking At

Sep 16

7 min read

Windows rarely fail all at once. They give you a symptom first, and the symptom is usually something small enough to live with, which is why most people live with it for a few years before calling anybody.

The useful thing is that the symptoms are fairly specific. A draft means one set of things. Fog between the panes means something completely different. Water on the sill means something different again. So rather than talk about repair and replacement in the abstract, here is what we actually find behind each of the common complaints, and what it usually means for the decision.

What you are seeing, and what it means

A draft you can feel. Usually the weatherstripping or the hardware, not the window. Weatherstrip hardens and compresses over fifteen or twenty years and stops sealing. Crank operators on casements wear so the sash no longer pulls tight against the frame. Both are replaceable, both are cheap, and both are worth checking before anyone quotes you a window. Verdict: repair, most of the time.

Fog or haze between the panes. The seal on the sealed glass unit has failed and the insulating gas fill has escaped. The window still keeps weather out, but it has lost most of its efficiency advantage and you cannot see through it properly. This is not a repair in any meaningful sense, but it is not a whole new window either. You replace the sealed unit and keep the frame and hardware. Verdict: replace the glass, keep the window.

Condensation on the inside surface of the glass in winter. Usually not a window problem at all. It means the humidity in the house is high enough to condense on the coldest surface in the room, and the glass is simply the coldest surface. Check the humidifier setting on your furnace and run the bathroom and kitchen fans properly. Verdict: no work needed.

Hard to open, hard to lock, or the sash drops when you let go. Hardware. Balances on a hung window wear out, crank operators strip, locks go out of alignment as a house settles. All replaceable in most cases. Verdict: repair.

Water pooling on the interior sill after rain. This one is worth taking seriously. It can be a failed exterior seal, but it can also be a flashing or drainage problem in the opening itself, which means water is getting into the wall and you are only seeing the small part of it that made it inside. Verdict: get it looked at properly before deciding.

Soft or spongy wood at the bottom corners of the frame. Rot, and rot at the corners of the sill is the classic place for it because that is where water sits. How far it has gone decides everything. Verdict: depends entirely on how much sound wood is left, and you cannot tell from the outside.

Peeling paint on the exterior trim only. Cosmetic and a maintenance question rather than a window question. Capping the trim in aluminum is often the better long-term answer than repainting it every five years, provided the wood underneath is dry and sound.

Noise. Older single-glazed or early double-glazed units do very little for sound. Nothing you can repair changes that. Verdict: replacement, if it bothers you enough to be worth the money.

The thing that usually decides it: parts

Here is the part that gets left out of every article on this subject, and in practice it decides more repair-or-replace calls than age does.

Window hardware is manufacturer specific. The balance in your hung window, the operator on your casement, the lock, the weatherstrip profile, the sealed unit thickness, all of it is particular to whoever made that window. So, the practical question is not whether your window can be repaired. It is whether the parts still exist.

Plenty of window companies that were selling into new Durham Region subdivisions in the 1980s and 1990s are no longer in business, or have discontinued the lines they were making then. When that happens, an otherwise sound window becomes unrepairable, not because anything is wrong with it but because nobody makes the piece anymore.

We can usually tell from a stamp on the hardware or in the spacer bar between the panes. It is worth asking about early, because it changes the whole conversation. A repairable window with available parts can keep going almost indefinitely. A sound window with no parts available is on a countdown regardless of what shape it is in.

Material matters more than age

Most people assume older means worse. With windows it is not that simple, and this catches people out.

Wood windows can be repaired more or less indefinitely as long as the wood is sound. Sashes come out, joints get repaired, rot gets cut out and pieced in, glazing gets redone. There are 90 year old wood windows in older parts of the region that are worth restoring and will outlast anything you could put in the hole.

Vinyl is different. Vinyl from the early generations gets brittle with UV exposure over the decades, and brittle vinyl cannot be repaired. Once the frame itself has degraded, there is nothing to fix. So, a 30 year old vinyl window can genuinely be a worse candidate for repair than a much older wood one.

Aluminum windows from the same period have their own issue, which is that without a thermal break the frame conducts cold straight through and sweats in winter. That is not a fault you can repair either.

The money, honestly

Repairs cost less today. That is the whole of their advantage, and it is a real one.

The way to weigh it is not a single price comparison. Add up what you have already spent on this window, add the repair in front of you, and then ask two questions: how many years is that buying, and are the parts still going to exist at the end of it. If you are spending real money to buy three years on a window whose parts are already scarce, that is expensive money.

There is one more piece that changes the arithmetic and it is easy to miss. Ontario's current window rebate applies to ENERGY STAR certified windows going into an opening. A repair does not qualify, because no certified window is going in. So, the gap between fixing and replacing is narrower than the two quotes suggest, and on a house with a lot of openings it can be quite a bit narrower.

We install ENERGY STAR 2020 certified windows and patio doors as standard, which since 2020 means a single national standard rather than the old climate zones. You can see the range on our windows and doors page.

Do you have to do them all at once?

No, and there are good reasons to stage it.

The sensible way to break up a whole-house job is by elevation rather than by room, so the exterior matches as you go. All the windows on the front, then all the windows on the back. Doing one here and one there leaves you with a visibly mismatched house for however long the project takes.

Two things to know if you are staging. Matching gets harder over time as product lines change, so if the look matters, ask whether the line you are choosing is likely to still exist in three years. And if you are claiming the rebate, it pays per opening, so there is generally no penalty for doing the work in batches, though the program has its own deadlines.

What a proper assessment should give you

Whichever way you are leaning, ask for it in writing.

A real assessment tells you what is wrong with each window specifically, not "your windows are old." It should tell you whether parts are still available, what condition the frame and the sill are in, and what happens if the frames turn out worse once something comes apart. Photos of what was found should come with it.

If somebody quotes a whole-house replacement without opening anything, looking at the hardware stamps, or asking what is actually bothering you, they have quoted a product rather than assessed a house.

Talk to us

John McLellan Contracting has been working on homes across Durham Region since 1995. More than 90 percent of our work comes from repeat and referral customers, and you don’t earn referrals by telling people to replace windows that could have been fixed.

Call (905) 767-1240 or book an assessment. You can see our window work in Pickering and Ajax, Whitby, and Oshawa.

Key takeaways

Match the fix to the symptom. Drafts and stiff operation are usually hardware. Fog between the panes is a failed sealed unit. Water on the sill may be the wall, not the window.
Interior condensation in winter is normally a humidity problem, not a failed window.
Parts availability decides more of these calls than age does. A sound window with discontinued hardware is on a countdown.
Material matters more than age. Sound wood can be repaired almost indefinitely. Brittle vinyl and non-thermally broken aluminum cannot.
The rebate applies to certified windows going into an opening, not to repairs, which narrows the gap between the two options.
Stage a whole-house job by elevation so the exterior matches as you go.

Frequently asked questions

How do I know whether to repair or replace a window?

Start with the symptom rather than the age. Hardware faults and worn weatherstripping are repairs. A fogged pane means replacing the sealed unit but not the whole window. Rot in the frame, a degraded vinyl or aluminum frame, or hardware nobody makes anymore point to replacement.

There is fog between my windowpanes. Can that be fixed?

The sealed glass unit has failed, and the insulating gas has escaped. You replace that unit and keep the frame and hardware, provided the frame is sound and a matching unit is still available. On some older or discontinued windows, it is not.

My windows sweat on the inside in winter. Are they failing?

Usually not. That is condensation from indoor humidity settling on the coldest surface in the room. Check your furnace humidifier setting and your exhaust fans before you call anyone about the windows.

Is it worth repairing a 25 year old window?

It depends on what it is made of and whether the parts exist. Sound wood is very repairable. Vinyl that has gone brittle is not repairable at all. Ask whoever assesses it to check the hardware stamps and tell you whether replacement parts are still available.

Can I replace just a few windows rather than all of them?

Yes. If you are doing it in stages, work by elevation rather than room by room so the outside of the house matches as you go, and be aware that matching a product line gets harder the longer you leave the remainder.

Does a window repair qualify for the Ontario rebate?

No. The current program applies to ENERGY STAR certified windows and doors going into an opening, so repairs, glass-only swaps, and maintenance work do not qualify. Check the current terms at saveonenergy.ca, since the amounts and deadlines change.