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Window and door contractors install units in new homes and additions, replace worn windows and entry doors in existing houses, repair hardware and glass, and take care of the details around each opening: the insulation and air seal between the frame and the wall, the flashing that sheds water, and the interior trim and exterior capping that finish the job. Many firms handle both windows and doors, which makes it easier to coordinate measurements, colours and finishes across the whole house.
This page is the starting point for the whole category. It covers the kinds of window and door work, the main styles, how glass and energy ratings work under the ENERGY STAR program in Canada, the winter problems that send homeowners looking for help, and the licences and permits to check before work begins. The pages on window installers, window replacement and exterior doors go deeper into each job.
Types of window and door work: installation, replacement, repair and glass
- New installation: windows and doors set into new or enlarged openings in a new home, an addition or a renovated wall.
- Window replacement: old units swapped for new ones, either as an insert inside the existing frame or with the whole frame removed.
- Door replacement: entry, side and patio doors replaced along with their frame, sill and weatherstripping.
- Glass replacement: a cracked pane or a fogged sealed unit swapped while the frame and sash stay in place.
- Hardware repair: cranks, hinges, locks, rollers and balances adjusted or replaced so a unit opens, closes and locks properly again.
- Sealing work: renewing the exterior sealant and the weatherstripping on units that are otherwise sound, a smaller job often booked before or after winter.
- Related specialties: garage doors, storm doors, screens and window film, which some window and door companies offer and others leave to specialists.
Window and door styles compared: casement, awning, hung, sliding and fixed
Style changes more than the look of the house. Windows that close by pressing the sash against its weatherstripping, like casements and awnings, generally seal tighter than those whose sashes slide past each other. The way a unit opens also decides how much fresh air comes in, how easy the outside of the glass is to clean and whether a bedroom window can serve as an exit in an emergency.
- Casement window: hinged on the side and opened with a crank, it catches breezes well and seals tightly when closed.
- Awning window: hinged at the top so it can stay open in light rain, common in basements and above fixed panes.
- Single- or double-hung window: one or both sashes slide up and down, a traditional look that suits many older and heritage homes.
- Sliding window: sashes glide sideways on a track, simple to operate but dependent on clean tracks and good brush seals.
- Fixed or picture window: it doesn't open, which makes it the most airtight option and the simplest way to frame a view.
- Entry and side doors: hinged doors, often with sidelights or a transom, chosen for security, insulation and curb appeal.
- Patio doors: sliding doors or hinged garden doors that open onto a deck or yard, where the glass area and the threshold matter most.
ENERGY STAR windows and doors in Canada: U-factor, Energy Rating and glazing
Natural Resources Canada administers the ENERGY STAR program for windows, doors and skylights sold in Canada. Under version 5.0 of the Canadian specification, in effect since January 1, 2020, a certified window or door must have a U-factor of 1.22 W/m²·K or lower, or an Energy Rating (ER) of 34 or higher, and meet an air leakage limit. Older brochures may still show a map of climate zones, but the current criteria apply across the whole country.
The figures on a label measure different things. The U-factor is the rate at which heat escapes through the product, so lower is better. The ER balances the U-factor, solar heat gain and air leakage in one score for windows and doors, so higher is better. The solar heat gain coefficient (SHGC) shows how much of the sun's heat passes through, and visible transmittance (VT) how much daylight does; for both, a higher figure means more gets in.
Those ratings come from the glazing and the frame working together: double or triple panes, a low-emissivity (low-e) coating that reflects heat back into the room, an inert gas such as argon between the panes and insulating spacers that keep the edge of the glass warmer. A window facing south can use a higher SHGC to collect winter sun, while one facing west that overheats in summer may call for a lower one, so ask the contractor to explain the ratings of each unit in the quote.
Winter window and door problems: condensation, frost and ice
Condensation on the inside of the glass is usually a humidity problem rather than a window defect. When warm, moist indoor air touches a cold surface, water forms, and in deep cold it turns to frost along the bottom of the glass and on the frame. New, tighter windows can make it more visible at first, because less air leaks out of the house and humidity rises. Running bathroom and kitchen fans, leaving blinds slightly open so warm air reaches the glass and keeping indoor humidity in check usually help.
Fog or moisture between two panes is a different story: the seal of the sealed unit has failed and moist air has got inside. It can't be wiped off, and the usual fix is a new thermos rather than a whole new window, as long as the frame is sound.
- Ice forming on the weatherstripping of an entry door, a sign that warm air is leaking past it.
- A door that drags or won't latch in winter, often because the frame or the house has moved with frost and moisture.
- Water stains or soft wood under a window sill, which point to a leak around the frame rather than through the glass.
- Patio door tracks that fill with ice, usually because the drain holes at the bottom of the frame are blocked.
Hiring one company for windows and doors: how the project comes together
Giving the windows and doors to the same company has practical advantages: one visit to measure every opening, frame colours and exterior capping that match, the same flashing and air-sealing details everywhere and a single contact if something goes wrong later. It also means one order from the manufacturer, and since most units are built to measure, the time between ordering and delivery usually sets the schedule.
- Visit and assessment: the contractor looks at each window and door, checks frames and sills for rot and talks through styles and glass.
- Written proposal: every unit is listed with its style, frame material, glazing, energy ratings and installation method.
- Final measurements: openings are measured precisely before the order goes in, since custom units can't be returned.
- Manufacturing and delivery: the date depends on the manufacturer's lead time, so plan ahead of the busy spring and fall seasons.
- Installation: units are replaced one opening at a time, so the house is never left open for long, even in cold weather.
- Finishing and walk-through: trim, capping and sealant are completed, and every unit is opened, closed and locked with you before the final payment.
Licences and permits for window and door work in Quebec and across Canada
In Quebec, a contractor whose main activity is window and door work for others needs a licence from the Régie du bâtiment du Québec (RBQ). The specialized subclass for this work is 8.0, doors and windows. Look up the contractor's licence and its subclasses on the RBQ website before you sign.
Whether replacing a window or door in the same opening needs a building permit depends on the municipality. Many require one when an opening is created, enlarged or moved, because that means cutting into the wall and adding a new header above it, and changing the look of a facade can need approval, particularly on heritage buildings or in protected areas. Ask your city before ordering, and agree in writing on who applies.
Window & Door Contractors: frequently asked questions
Should I replace my windows and doors at the same time?
Not necessarily, but doing them together simplifies ordering, lets colours and trim match and means air sealing and flashing are handled the same way everywhere. If you need to phase the work, start with the units in the worst condition or on the side of the house most exposed to wind.
What does ENERGY STAR certified mean for a window or door in Canada?
The model meets Natural Resources Canada's criteria: under version 5.0 of the specification, a U-factor of 1.22 W/m²·K or lower, or an Energy Rating of 34 or higher, plus an air leakage limit. The certification applies to the product, so a careful installation is still needed to get that performance in your home.
Double or triple glazing: which is better for a Canadian home?
Triple glazing insulates better and keeps the inner pane warmer, which helps comfort and reduces condensation in very cold regions, but the units are heavier and more expensive. Good double glazing with a low-e coating and gas fill can also meet ENERGY STAR criteria, so compare the U-factor or ER of each option rather than just counting panes.
Does a window and door contractor need a licence in Quebec?
Yes. A contractor who does this work for others needs an RBQ licence, and subclass 8.0 covers doors and windows. Check the licence number on the RBQ website before signing a contract.
Sources
- Windows, doors and skylights – ENERGY STAR Canada technical specification — Natural Resources Canada
- Ratings and certification: windows, doors and skylights — Natural Resources Canada
- Keeping the Heat In, Section 8: Upgrading windows and exterior doors — Natural Resources Canada
- Specialized contractor licence subclasses — Régie du bâtiment du Québec
- Check a contractor's licence — Régie du bâtiment du Québec
Written by the LokalMatch editorial team. Reviewed by Zubair Afzal on September 10, 2026. How we write and check our guides
