How to Prepare Your Windows for a Montreal Winter: Tracks, Screens, Seals and Condensation

To prepare your windows for a Montreal winter, do four things before freeze-up: clean the glass, tracks and weep holes so the windows close and drain properly, decide whether screens come off, check the weatherstripping and exterior caulking while temperatures are still mild, and plan to keep indoor humidity lower once the cold sets in. Most of this takes an afternoon, and it's much easier in October than in January when the frames are frozen.

Here's the checklist, room by room, with what to watch for in Greater Montréal homes.

1. Clean the glass while you still can

Exterior window cleaning in Greater Montréal is seasonal. Once daytime temperatures stay around freezing, usually some time in November, water freezes on the glass and outdoor cleaning stops until spring. Anything on the exterior glass when that happens stays there for months.

A fall cleaning also makes a visible difference in winter light. With short days and the sun low in the sky, dirty glass and dusty screens show every streak and cut the light coming in. Clean glass is the cheapest way to make a house feel brighter between December and February.

2. Clear the tracks and weep holes

This step matters more than the glass for how your windows perform in winter.

Tracks. Sliding windows and patio doors collect grit, seeds, dead insects and dust in the bottom track all summer. That debris stops the sash from sliding fully closed and from sitting tight against the weatherstripping. A window that doesn't close fully lets in cold air and can frost up along the gap. Vacuum the track, then wipe it with a damp cloth. A small brush or an old toothbrush gets into the corners.

Weep holes. Many vinyl and aluminum windows have small drainage slots on the outside of the bottom frame. They let rainwater that gets into the frame drain out. When they're blocked with debris, water sits in the frame and freezes. Check that they're clear; a pipe cleaner or a thin wire usually does it. Don't seal them with caulking. They're supposed to be open.

3. Decide what to do with the screens

There's no rule, but many Montreal homeowners take screens off for the winter.

Reasons to remove them:

• More daylight gets in when it's scarce.
• Snow and ice don't build up against the mesh.
• The screens last longer stored dry than left out through freeze-thaw cycles.

If you take them off, wash them first, let them dry completely, label which window each one belongs to, and store them flat or upright in a dry garage, shed or basement. If you leave them on, at least wash them. A dirty screen in front of clean glass undoes most of the effect.

In older Plateau and Rosemont plexes with exterior storm windows, the storms usually go on in the fall and the screens come off. If you have a triplex with original windows, check that the storm windows are clean on the inside surface before they go up; you won't reach that surface again until spring.

4. Check weatherstripping and caulking

While you're at each window, look at the seals.

• Weatherstripping on the sash should be flexible and continuous. Cracked, flattened or missing sections let drafts through. Many types can be replaced by a homeowner.
• Exterior caulking around the frame should be intact. Gaps or cracked caulk let water and air in. Caulking products list a minimum application temperature, so if you need to re-caulk outside, do it on a mild fall day rather than waiting.
• Interior trim gaps can be sealed with interior-grade caulk any time.

Natural Resources Canada and Hydro-Québec both publish guidance on air sealing around windows if you want to go further.

5. Plan for condensation

Condensation on the inside of windows is one of the most common winter complaints in Greater Montréal. It happens when warm, humid indoor air meets cold glass. In deep cold, frost can form along the bottom of the glass, and if it melts and drips repeatedly it damages wood sills and frames and can lead to mould.

The fix is mostly about indoor humidity, not the window.

• Keep indoor humidity lower as it gets colder. CMHC and Natural Resources Canada both advise reducing indoor relative humidity in cold weather to limit condensation. A general guideline is somewhere between 30 and 50 percent, with the lower end during the coldest stretches. An inexpensive hygrometer tells you where you are.
• Run exhaust fans in bathrooms during and after showers and over the stove while cooking.
• Use your HRV if you have one, and clean its filters in the fall.
• Open blinds and curtains during the day so warm room air reaches the glass. Heavy curtains closed tight against windows overnight make condensation worse.
• Turn off or turn down humidifiers when you see moisture on the glass.

If you see condensation between the panes of a double- or triple-glazed unit, that's different. It means the seal on the sealed unit has failed, and cleaning won't fix it. The glass unit needs replacement.

6. Don't forget the interior in winter

Exterior work stops in the cold, but interior windows can be cleaned all year. Winter often leaves a hazy film on the inside of the glass from cooking, heating, candles and fireplaces. An interior-only cleaning in late winter can brighten a house before spring arrives.

When to call a professional

Most of this checklist is homeowner-friendly. Where a professional helps is the exterior glass on upper storeys, screens and tracks on many windows at once, and homes with lots of divided-light or hard-to-reach windows. Altara serves homes across Greater Montréal, including the Montréal and Laval areas. Our flat rate, set by the window-count tier you pick online, covers the exterior glass, frames and sills, cleaned with pure water on a water-fed pole that reaches up to three storeys, with screens rinsed in place. Interior glass, screen removal and washing, and track cleaning can be added on request at extra cost.

Frequently asked questions

Why do my windows get condensation in winter?

Condensation forms when warm, humid indoor air touches cold glass and the moisture in the air turns to water. It's most common in bathrooms, kitchens and bedrooms and on the coldest days. Lowering indoor humidity, running exhaust fans and keeping air moving across the glass usually reduces it.

Should I take my window screens off for winter in Quebec?

Many Quebec homeowners do, because removing screens lets in more winter light, keeps snow and ice from building up on the mesh, and helps the screens last longer. Wash them, let them dry completely and label them before storing them somewhere dry. Leaving them on is fine if you'd rather not deal with it, but have them cleaned in the fall.

Can I caulk windows in cold weather?

Most caulking products have a minimum application temperature printed on the tube, and many don't cure properly in the cold. Exterior caulking is best done on a mild, dry fall day. Interior caulking around trim can be done any time since the house is heated.

What does condensation between window panes mean?

Moisture or fog between the panes of a double- or triple-glazed window means the sealed unit has failed and outside air has gotten in. It can't be cleaned away from the outside or inside. The sealed glass unit usually needs to be replaced, often without replacing the whole frame.

Get your windows ready for winter

Pick your window-count tier on our pricing page and book your exterior clean before freeze-up, adding interior glass, screens or tracks if you want them. Questions? Use our contact form.