When to Replace Your Windows — and How to Choose a Contractor in the GTA

Window replacement is one of the larger home improvement expenses — typically $800 to $2,000+ per window installed, depending on size, material, and configuration. That makes it important to get two things right: knowing when replacement is genuinely necessary, and choosing a contractor who won't let you down.

Signs Your Windows Actually Need Replacing

1. Visible seal failure on double or triple-pane units

If you see fogging, condensation between the glass panes, or a milky residue that won't clean off, the sealed glass unit has failed. The argon or krypton gas has escaped and the insulating value of that unit has dropped significantly. This cannot be repaired — the glass unit must be replaced.

2. Drafts that persist after weatherstripping replacement

Weatherstripping is a normal maintenance item — it compresses over time and should be replaced periodically. But if you've replaced the weatherstripping and still feel cold air around the frame, the problem is in the frame itself: warping, cracking, or separation from the rough opening. That's a replacement conversation.

3. Frame deterioration

Wood frames rot. Older aluminum frames can corrode at the joints. UPVC frames can warp or crack if they weren't installed correctly or were exposed to significant impact. When the frame is compromised, no amount of sealing makes the assembly perform properly again.

4. Operation difficulty

Windows that are very difficult to open, won't stay open, or won't close and latch securely are a safety issue in addition to a performance issue. Sometimes this is a hardware problem (replaceable). When the sash itself has warped or the frame has racked, replacement is the answer.

5. Single-pane glass

If your home still has original single-pane windows, replacement is almost certainly worth doing from an energy and comfort standpoint regardless of condition. The thermal performance difference between single and double-pane glazing is very large.

How to Choose a Window Contractor in the GTA

Ask who does the installation

A significant portion of window companies in the GTA are sales organizations that subcontract installation to third parties. This isn't automatically a problem, but it means the company you're buying from has less direct accountability for how the job is done. Ask specifically whether the installation crew is employed by the company or contracted.

Check for WSIB and liability insurance

Any contractor working on your home should carry WSIB coverage (Workplace Safety and Insurance Board) and general liability insurance. Ask for certificates before work begins. If there's resistance to providing these, that's a significant red flag.

Get three quotes — but don't just compare the number

The three quotes you receive will likely vary by 20% to 40%. Before comparing prices, make sure you're comparing the same specification: same product line, same glass package, same installation method. A lower quote that uses a different glass specification or omits air sealing is not a like-for-like comparison.

Ask about the warranty — both parts of it

Window warranties have two components: the sealed glass unit (typically 20–25 years from the manufacturer) and the installation workmanship (varies widely, from 1 year to lifetime). The installation warranty matters as much as the product warranty — most failures occur at the installation interface, not in the glass unit itself.

Visit a project they've completed

A confident contractor will offer references and ideally an address of a completed project you can drive by. Seeing finished work in person tells you things a showroom visit can't.