Fix Draft Coming from Windows

The real culprit is often weatherstripping, not the glass itself. Even new windows leak air if seals are damaged or improperly installed. Fix path: free diagnosis → cheap seal → medium insulation → advanced fix.

Free Diagnosis (Do This First)

1. Wet hand test: Wet your hand, move it slowly around window frame edges. You'll feel cold airflow instantly where leaks exist.
2. Candle test: Hold a lit candle near frame edges on a windy day. Flame flickers = leak location.
3. Check both sides: Interior trim AND exterior caulking. Both matter.

Quick Fix ($5-15, 30 minutes)

1. Weatherstripping tape: Apply foam tape to interior frame where sash meets frame. Press firmly, no gaps. Lasts 1-2 seasons.
2. Rope caulk: Press into visible gaps along frame. Removable, renter-friendly. Works immediately.

Proper Fix ($15-40, 1-2 hours)

1. Remove old weatherstripping: Scrape off deteriorated material with putty knife.
2. Clean surfaces: Rubbing alcohol on rag. Must be dry and dust-free.
3. Apply silicone caulk: Exterior gaps between frame and siding. Interior gaps between frame and drywall. Smooth with wet finger. Cures 24 hours.
4. Install V-seal or compression weatherstripping: Cut to length, peel-and-stick. Metal V-seal lasts 5+ years.

If Draft Persists

Check these overlooked sources:

• Window lock not engaged: Modern windows compress weatherstripping when locked. Unlocked = gap.
• Sash misalignment: If window frame is warped or settling caused shift, weatherstripping won't contact properly. May need pro adjustment.
• Wall cavity air leaks: Draft may be coming from BEHIND drywall through electrical boxes or gaps, exiting near window. Feel for air at outlets on same wall.

Pro tip: Do the candle test AFTER sealing. If flame still flickers significantly, the leak is in the wall cavity behind the window, not the window itself — that's a drywall/insulation issue requiring different approach (outlet gaskets, spray foam in wall penetrations). Most people waste money replacing windows when the problem is actually the rough opening.