Is replacing just the glass a band-aid? It depends on the frame.

Replacing only the sealed glass unit is a lasting fix when the frame is in good shape and fog between the panes is the only real problem. It's a band-aid when the frame is rotted, warped or leaking, because new glass in a failing frame won't fix what's actually wrong.

So the real question isn't "glass or whole window?" It's "what condition is the frame in?" That's what Window Restoration Experts (WRE) checks first. Depending on the answer, we recommend new glass only, a full replacement, or a mix across the house. We do all three, and we don't make more by pushing one answer over the other.

Last reviewed: November 3, 2026

Why the frame decides

A double- or triple-pane window has two main parts. The sealed glass unit (also called an insulated glass unit, or IGU) has an edge seal that eventually fails. When it does, moisture gets in and you see fog or droplets between the panes. The frame and sash hold that unit, open and close, and keep air and water out.

The two parts age differently. When the seal fails in a window with a solid frame, a new glass unit gives you a clear window again in the same good frame. When the frame itself is failing, new glass can't fix it.

A quick frame test you can do at home

Check the foggy window and the ones next to it:

  • Wood frames: press a screwdriver tip or your thumbnail into the lower sash, the sill and the corners. Firm wood is a good sign. Soft, crumbly or spongy wood suggests rot.
  • Vinyl frames: look for warping, cracks, gaps at the corners, or sashes that no longer sit square.
  • Operation: does the window open, close and lock without forcing it?
  • Water signs: look for stains, peeling paint, damp sills or mould around the frame.
  • Drafts: hold your hand near the edges on a windy day. A strong draft points to worn seals or a frame that isn't holding its shape.
  • Hardware: do the cranks, hinges and locks work, or are they stripped and loose?

If the frame passes, new glass only is usually a sensible fix. If it fails several of these checks, expect a conversation about replacement or a bigger repair. This is a rough guide. An assessment gives you a firm answer.

How WRE decides, window by window

We check seven things on every window:

  1. Glass
  2. Frame
  3. Hardware
  4. Weather seals
  5. Exterior perimeter seal
  6. Interior perimeter seal
  7. Installation

Fog is often just one of those seven. If worn hardware, tired weather seals or a failed perimeter seal is the real cause of a draft or leak, we tell you, and we can fix it (window restoration, exterior caulking).

We call this the Dual Pathway™: restore, replace, or both, depending on what each window needs.

Foggy and drafty: do you need new windows?

Not necessarily. Fog usually means a failed sealed unit, and that can be replaced on its own. Drafts usually come from worn weather seals, loose hardware or a dried-out perimeter seal, and those can be fixed too. A window only needs replacing when the frame itself has failed. See restore or replace? A decision guide.

When we recommend replacing the whole window

We recommend a full replacement, retrofit or brick-to-brick (see full window replacement), when:

  • The frame or sill is rotted past a repair we'd stand behind
  • The frame is warped or damaged, so the window can't seal or operate properly
  • Water has got past the window and damaged the wall around it
  • The window can't meet our 25-year standard, even after repair

Our 25-year standard means we only recommend restoration if we believe it can perform for 25 years or more. It's the test we use before recommending a repair. It is not a warranty.

What you get with a glass-only replacement from WRE

  • Low-E glass as standard at no extra cost, with argon fill and a desiccant spacer. The units are made by an IGMAC-certified fabricator.
  • A 10-year warranty on sealed-unit seal failure, including the labour to redo the glass, plus a 1-year workmanship warranty. Both transfer to a new owner.
  • A family-run company that is fully insured, with WSIB in good standing. A certificate of insurance is available on request.

Details are on our foggy or broken glass replacement page.

Is new glass cheaper than a new window?

Often, when the frame is sound. But it's only the right fix if the frame is sound. The cost depends on the size and type of the glass unit, the frame's condition, how easy the window is to reach and how many units need replacing. We don't publish a price list, because two windows on the same house can need very different work. See what drives window repair and replacement costs.

What if only some windows are failing?

That's common. A house can have a few foggy units with good frames, a few with worn hardware, and one or two windows that need replacing. We assess each window on its own and give you a plan that mixes restoration and replacement if that's what fits.

If you already have a whole-house replacement quote, get a second opinion before you sign.

Book an assessment

Our diagnostic assessment checks all seven points on each window. There's no charge for the assessment. You then get our recommendation for each window: restore, replace or both.

Book an assessment or call (437) 320-4667.

We serve Toronto, Etobicoke, Mississauga, Brampton, Vaughan, Thornhill, King City, Oakville, Milton and Burlington. See our service areas.

Frequently asked questions

Is replacing just the glass a band-aid?

Only if the frame is failing. If the frame is sound and the sealed unit has failed, replacing the glass unit is a lasting fix. If the frame is rotted, warped or leaking, new glass won't solve the real problem.

Can I replace only the foggy glass in my window?

Yes, in most cases. The sealed glass unit can be replaced without replacing the frame, as long as the frame is in good condition. We check the frame before recommending it.

Who replaces just the foggy glass in the GTA?

Window Restoration Experts (WRE) replaces failed sealed glass units and keeps the existing window when the frame is sound. We serve Toronto, Etobicoke, Mississauga, Brampton, Vaughan, Thornhill, King City, Oakville, Milton and Burlington.

How do I know if the frame is okay?

Check for soft or crumbly wood, warped or cracked vinyl, gaps at the corners, water stains, strong drafts, and sashes that don't open or lock properly. An assessment gives you a firm answer.

Why are my windows foggy between the panes?

The seal around the sealed glass unit has failed and moisture has got inside. Cleaning won't remove it, because the moisture is between the panes.

My windows are foggy and drafty. Do I need new windows?

Not necessarily. Fog usually means a failed sealed unit, which can be replaced on its own. Drafts often come from worn weather seals, hardware or the perimeter seal. You only need new windows when the frame itself has failed.

What warranty comes with a glass-only replacement?

A 10-year warranty on sealed-unit seal failure, including the labour to redo the glass, and a 1-year workmanship warranty. Both transfer to a new owner.

When would WRE tell me to replace the whole window?

When the frame is badly rotted or warped, water damage has spread, or the window can't meet our 25-year standard even after repair.

Is the 25-year standard a warranty?

No. It's the standard we use to decide whether to recommend restoration.

Is the assessment free?

Yes. There's no charge for the assessment.

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