How to Fix a Window That Lets in Draft

Drafty windows are one of the biggest sources of energy loss in a home. A single drafty window can add significantly to your heating and cooling bills. Here's how to find every draft and seal it effectively.

How to Find Window Drafts

On a cold or windy day, hold a lit candle or incense stick near the window edges. Watch for the flame or smoke to flicker — that's where air is getting in. Check all four sides of the frame, the corners, and around the lock hardware.

Common Draft Locations

Between the sash and the frame (worn weatherstripping)
Between the frame and the wall (failed caulk)
Around the lock hardware
Through cracks in the frame or sash
Through the glazing compound around the glass

Fix 1: Replace Weatherstripping (Most Common Fix)

Worn or compressed weatherstripping is the #1 cause of window drafts. Replace it on all four sides of the sash.

Weather Stripping Brush Pile Self-Adhesive 16.5ft — designed for sliding windows; pile brush seals irregular gaps perfectly
Foam Weather Stripping Seal Tape 16ft (1/2" x 1/4") — self-adhesive foam for sealing around window stops and frames

Fix 2: Recaulk the Frame-to-Wall Joint

The joint between the window frame and the wall is a major draft source, especially in older homes. Remove old caulk and apply fresh silicone caulk.

GE Advanced Silicone Caulk Window & Door Clear — 100% waterproof, freeze and sun proof, 5x stronger adhesion; ideal for window frame sealing
Bates Caulking Gun 10:1 No Drip — smooth, controlled application

Fix 3: Apply Window Sealing Tape

For a quick seasonal fix, apply transparent window sealing tape around the sash perimeter. This is removable and won't damage the frame.

XFasten Transparent Window Sealing Tape 2"×30yd — clear, no residue, easy removal; seals drafts without blocking light

Fix 4: Install a Window Insulation Film Kit

For maximum draft reduction in winter, apply a shrink-film insulation kit over the entire window. This creates an insulating air gap and eliminates all drafts.

Frost King Indoor Shrink Window Kit 42"×62" 9-Pack — clear film shrinks tight with a hair dryer; eliminates drafts completely for the season

Fix 5: Repair Glazing Compound

On older single-pane windows, the glazing compound (putty) around the glass can crack and shrink, creating gaps. Remove old glazing and apply fresh compound.

DAP '33' Window Glazing White 32oz — professional-grade glazing compound for single-pane windows

Energy Savings Potential

Sealing drafty windows can reduce heating and cooling costs by 10–20%. A $20 weatherstripping and caulk job can save hundreds of dollars per year on energy bills.

Priority Order

Replace weatherstripping (biggest impact, easiest)
Recaulk frame-to-wall joint
Apply window sealing tape for quick seasonal fix
Install shrink film for maximum winter protection
Repair glazing compound on single-pane windows

Back to blog