The Playbook for Hiring a Window Installer in Canada: Cold-Weather Installation, Air Sealing, and What a Good Quote Includes

Window Wise: the certification NRCan points to

There is no national licence for window installers. The credential that comes closest is Window Wise, and the federal government names it directly. On its ENERGY STAR page for windows, Natural Resources Canada warns that a poorly installed window can cause condensation, cold drafts or water leaks, and recommends choosing installers certified through the Window Wise quality assurance program.

Window Wise is run by the Siding and Window Dealers Association of Canada (SAWDAC). According to Fenestration Canada, it certifies replacement-window manufacturers and installation contractors through independent audits and training built on CSA A440.4, and certified installations carry a five-year transferable guarantee. That guarantee is the key feature. It is designed to protect the homeowner regardless of what happens to the contractor.

Many manufacturers also run their own certified or authorized installer programs. They are worth asking about, especially if the product warranty is conditional on an authorized installation. Ask for the program name and confirm it with the manufacturer, not the salesperson.

Insurance, workplace coverage and warranty minimums

Credentials beyond certification are about who pays if something goes wrong. The federal Office of Consumer Affairs tells homeowners to confirm the contractor is certified, to ask about liability insurance and any required workers' compensation coverage, and to check references from recent clients.

The RenoMark code of conduct is a useful benchmark even if your installer is not a member. RenoMark renovators commit to a minimum two-year warranty, a detailed written contract with a scope of work, at least $2 million in liability insurance, and subcontractors with workplace safety coverage.

In Ontario, the WSIB clearance lookup lets anyone confirm that a business is registered and current with its premiums. The WSIB also states that a clearance certificate is not required when a contractor is hired by the home's resident for repairs or renovations, so this is a due-diligence signal rather than a legal duty. It is still a fast way to learn whether the company you are about to pay is operating above board.

The hiring pattern is the same across trades. Our playbook for hiring a roofer covers the same credential checks for another envelope trade.

The general rule, and its exceptions

Most like-for-like replacements in a single-family house do not need a permit. The exceptions are specific and easy to trip over. The City of Toronto exempts window replacement in a detached, semi-detached or single-unit row house only when the size and location of the opening don't change, the structural support isn't altered, and no new exit is created.

A permit is needed for a new opening, an enlarged or relocated opening, or replacement in any other building type. That last point catches owners of duplexes and triplexes, who often assume their property counts as a house.

Municipalities set their own rules within their province's code, so treat Toronto's list as a model of the questions to ask, not the answer for your address. The quote should say who confirms the permit requirement and who pulls it if one is needed.

Bedroom windows and egress

Replacing a bedroom window can quietly break a life-safety requirement. Under the 2024 Ontario Building Code, the City of Ottawa's egress advisory states that an egress window must provide an unobstructed opening of at least 0.35 m² with no dimension less than 380 mm, open from the inside without tools, and (outside basements) have a sill no higher than 1,000 mm. Window wells need 550 mm of clearance in front of the window.

The rough opening can stay exactly the same while the openable area shrinks. Swapping a casement for a slider, or adding a thicker frame, can drop a window below the minimum. Ask the installer to confirm the clear opening of the new unit against the requirement before you order.

Planning a new basement opening rather than a replacement? That is a different project, covered in our guide to adding egress windows to a basement.

Pin down the unit before you compare the installation

The unit specification is the easy half, but only if it is written down precisely. ENERGY STAR Canada no longer uses regional climate zones. Under the current ENERGY STAR Canada specification (Version 5.0, in effect since January 1, 2020), one standard applies across the country: a window qualifies with a U-factor of 1.22 W/m²·K or lower, or an Energy Rating of 34 or higher.

A U-factor measures how easily heat passes through the whole window, so lower is better. The Energy Rating (ER) combines heat loss, solar gain and air leakage into one number, so higher is better. A quote should list both, along with the frame material, operator type and glazing package for each opening. Certified windows carry a temporary label showing the U-factor, ER, solar heat gain and visible transmittance, plus a model code or NRCan reference number. Match that code to the quote on delivery day.

The matrix

Lay each quote over this table. Mark every line Included, Missing or Negotiable. A quote with more than two or three "Missing" marks is not ready to compare.

The furnace trade has the same scope-versus-equipment problem; our guide to reading a furnace quote uses the same audit logic.

Use these as a script. Each one maps to a row in the matrix, and each answer should end up in writing.

• Will each opening be an insert or a full-frame installation, and why?
• Will you install to CSA A440.4 and the manufacturer's instructions, and will you put that in the contract?
• What sill protection will you use: a sill pan, sub-sill flashing, a back dam or a sloped sill?
• Which foam goes in the cavity, and is it a low-expansion window-and-door product?
• How do you make the interior air seal, and what connects it to the wall's air and vapour barrier?
• Which exterior sealant and flashing tape will you use, and what are their minimum application temperatures?
• If it drops below those temperatures on install day, what do you do?
• Are your installers Window Wise certified or authorized by the manufacturer, and can I confirm that?
• What is your installation warranty, separate from the product warranty, and is it transferable?
• Who confirms whether a permit is needed, and for bedroom windows, what is the clear opening of the new unit?

If a rebate is in play, the timing matters before you sign. Ontario's Home Renovation Savings Program, according to a July 2026 program guide, pays $100 per rough opening for ENERGY STAR windows but requires a home energy assessment before any work begins and at least two qualifying upgrades. Confirm the current rules on the program's own site before you book the assessment.

Other provinces run their own programs with their own sequencing rules; our province-by-province window rebate breakdown tracks them.

Hold back the final payment until you have walked every opening. A short inspection now is far cheaper than a warranty claim in February.

Check the delivered units first. The model code on each temporary label should match the quote. Then open, close and lock every sash. Binding or a lock that suddenly needs force can mean a frame was bowed by foam or fastened too tightly.

Look at the exterior. The perimeter should be capped or trimmed and fully sealed, with no gaps at the corners and no sealant smeared over weep holes at the bottom of the frame. Inside, the trim should be installed, filled and caulked, and any debris or old units gone.

Then watch the glass through the first cold snap. Some condensation after replacement is a humidity signal rather than a defect. As NRCan explains, old, leaky windows actually helped keep indoor humidity down, and a tighter house holds more moisture unless you reduce humidity or improve ventilation. Condensation at the edge of the glass on a cold morning is usually that. A cold draft at the trim, water on the sill or frost on the inside of the frame points back to the installation.

For the drafts that remain elsewhere in the house after the new windows are in, our guide to draft-proofing a Canadian house covers the doors, trim and penetrations the window crew won't touch.

Get the paperwork before the last cheque: the signed contract, both warranties, the product registration (if the manufacturer requires it), any permit sign-off, and any Window Wise registration for the job.