If you’re planning to upgrade your home’s windows, you’ve probably wondered:
Can a general contractor install windows?
And more importantly, how much do contractors charge for window replacement in Ontario or across Canada?

These are smart questions—and not just about budget. Hiring the right person to install your windows means avoiding cold drafts, water damage, failed warranties, and sky-high utility bills. In this guide, we’ll break down what general contractors can (and can’t) do, how much window replacement really costs, and what to look for when hiring the right pro.

What Does a General Contractor Do?

A general contractor (GC) is a licensed professional who oversees construction or renovation projects. They may coordinate tradespeople, schedule jobs, obtain permits, and manage timelines. In most cases, a GC will subcontract out specialized jobs like HVAC, roofing, electrical, and yes, even window installations.

But here’s the thing: just because a GC manages your renovation doesn’t mean they personally install your windows.

So… Can a General Contractor Install Windows?

Yes—but with conditions.

Legally speaking in Ontario and across Canada, a general contractor can install windows if they are qualified, experienced, and properly insured. However, not all GCs are trained window installers, and not all installations are straightforward.

Infographic comparing the pros and cons of general contractors (GC) installing windows.

Here’s what to consider:

✅ When It’s Okay

  • The GC has direct experience installing windows

  • They are WSIB-insured and have liability coverage

  • They follow Ontario Building Code regulations

  • The window type is basic (like retrofit vinyl sliders or casements)

  • The GC uses or supervises certified window crews

⚠️ When You Should Be Cautious

  • No track record with window installs

  • No proper insurance or warranty coverage

  • They outsource the job to unknown subcontractors

  • They can’t explain flashing, insulation, or sealing methods

  • They offer a low quote that sounds “too good to be true”

Bottom line: A GC can legally install windows, but skill and experience matter more than titles.

Pros of Hiring a GC for Window Installation

If your window replacement is part of a larger renovation, hiring a GC can simplify your project. Here’s how:

  • One point of contact for multiple jobs (windows, siding, drywall, trim)

  • They handle permits and inspections

  • They can coordinate with your window supplier

  • They’ll often bring in their own installation team

  • Great for additions or structural modifications

Cons of Hiring a GC Instead of a Window Specialist

That said, there are downsides if the contractor isn’t a specialist:

  • Window installation requires precision and sealing knowledge

  • Incorrect installation = water leaks, heat loss, fogging

  • May void manufacturer warranties if not installed to spec

  • Can lack the product knowledge you’d get from a window company

  • Might use inferior materials or skip crucial insulation steps

Should You Hire a Window Specialist Instead?

A window installation professional wearing gloves and an orange shirt aligns a white vinyl window frame inside a residential home, with a green backyard visible through the glass.

If your focus is only replacing windows (not a full renovation), a dedicated window company like Polaris Windows & Doors is usually the better choice. Here’s why:

How Much Do Contractors Charge for Window Replacement?

If you’re searching “how much do contractors charge for window replacement,” here’s a breakdown of what to expect in the GTA and surrounding areas like Vaughan, Mississauga, and Scarborough:

Window Type Estimated Price (Installed)
Standard Vinyl Casement $500 – $1,000 per unit
Double Hung Window $450 – $800 per unit
Bay or Bow Window $2,000 – $4,500+ per unit
Sliding Basement Window $300 – $600
Labour Only (Retrofit Style) $150 – $300 per window
Full Frame Installations $250 – $500+ labour per window

Prices vary based on:

  • Window size and type

  • Retrofit vs full-frame install

  • Access to the window (upper floor, tight areas)

  • Finish trims, caulking, foam insulation

  • Whether permits are required (e.g., for new openings)

Want a detailed price breakdown? See our post on How Much Does It Cost to Replace Windows

What to Ask Before You Hire

Whether you’re going with a general contractor or a window specialist, ask these questions:

  • Are you licensed and insured for window installation in Ontario?

  • Do you have experience with the type of window I’m installing?

  • Will your work meet Energy Star and building code standards?

  • Who does the actual install—you or subcontractors?

  • What type of warranty do you offer?

  • Can you provide references or past project photos?

Final Thoughts: Who Should Install Your Windows?

So, can a general contractor install windows? Yes—but only if they know what they’re doing.
The better question is: should they?

If your window upgrade is part of a bigger renovation, a qualified GC may be a convenient option—just make sure they’re using experienced installers. If your project is window-specific, a specialized company like Polaris Windows & Doors gives you peace of mind, full warranty coverage, and energy performance tailored to Canadian weather.

And if you’re wondering how much do contractors charge for window replacement, remember: it’s not just about price—it’s about value, installation quality, and long-term savings.

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Get a free quote from Polaris Windows & Doors, and see why homeowners trust us for their window replacements.

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