Drafty Windows? How to Tell If You Need Replacements Before Winter

If you feel cold air near closed windows, see fog or frost between the glass panes, notice soft or rotted wood on the frame, or have to fight to open and lock them, those windows are losing heat and money every winter. Some problems are a cheap fix. Failed seals and rotted frames mean replacement.

Quick at-home draft test

On a cold, breezy day — a Twin Cities December afternoon in the 20s°F is ideal — hold a lit incense stick or a thin tissue near the sash edges, lock, and corners. If the smoke or tissue moves, air is getting through. Check every window; the worst ones are usually on the windward side of the house.

Repair vs. replace: how to tell

Usually a repair: worn weatherstripping, a loose lock, gaps in the exterior caulk, a missing sash balance. Usually a replacement: fogging between the panes, rotted or crumbling frames, single-pane glass, sashes painted or swollen shut, or condensation and frost forming on the inside glass every cold morning.

Condensation between the panes = failed seal

A double-pane window has a sealed gas fill between the panes. When you see haze, water droplets, or a mineral film that you can't wipe off because it's inside the glass, the seal has failed and the insulating value is largely gone. That unit won't recover.

What new windows save in a Minnesota winter

Old leaky windows can account for a noticeable share of a home's heat loss. Replacing single-pane or seal-failed units with modern low-E, gas-filled glass cuts drafts, stops the cold-glass chill near seating, and reduces interior condensation and frost. The comfort change is immediate; energy savings add up over the years.

Glass and frame features that matter here

• U-factor 0.27 or lower for our climate zone — the lower the number, the better it holds heat.
• Low-E coating and argon fill standard; triple-pane is worth considering for rooms with seating against the window.
• Warm-edge spacers to reduce condensation at the glass edge.
• Insulated frames — vinyl or fiberglass — rather than bare aluminum, which conducts cold.

Timing: fall installs are fine

Windows are swapped one opening at a time and closed back up within an hour or two, so replacement runs comfortably into late fall and winter. See window services.

Pair with attic air sealing

Drafts you feel at the window are often part of a bigger air-leakage picture. Sealing and insulating the attic at the same time gives the biggest comfort gain per dollar. See insulation services.

Frequently asked questions

Can windows be replaced in winter in Minnesota? Yes — one at a time, with the opening sealed back up quickly.

What U-factor should I look for? 0.27 or lower for the north metro.

Is interior condensation always a bad window? Not always — it can mean high indoor humidity. Frost every morning on the glass points to a poor-performing window.

How long does a whole-home window job take? Usually two to four days.

Get a window assessment

Total Home Exteriors has replaced windows across the north metro since 2003. Call 612-388-7795 or request a free assessment.