How do I fix a drafty window?

Drafty windows are typically caused by worn weatherstripping, gaps in the frame, or poor sealing around the window unit itself. Most draft issues can be resolved with some basic materials and a few hours of work, though severe cases may require professional window replacement.

The first step is identifying where the draft is coming from. On a windy day, hold a lit candle or incense stick around the window frame, sash, and glass edges. The flame will flicker or smoke will move where air is infiltrating. Common problem areas include the bottom sash rail, where the upper and lower sashes meet, around the window frame where it meets the wall, and along worn weatherstripping.

For weatherstripping replacement, remove the old material completely and clean the surface with rubbing alcohol. V-strip weatherstripping works well for the sides of double-hung windows, while foam tape or tubular gaskets are effective for the bottom rail and top of the frame. Quality weatherstripping from brands like Frost King or Duck Brand costs $15-30 per window and should last 3-5 years in Ottawa's harsh freeze-thaw climate.

Caulking gaps around the exterior window frame is crucial for Ottawa homes. Remove old, cracked caulk with a utility knife, clean the area thoroughly, and apply a high-quality exterior caulk rated for temperature extremes. Polyurethane or hybrid polymer caulks perform better than basic acrylic in our climate. This work is best done when temperatures are above 10°C for proper curing.

For interior solutions, consider adding rope caulk as a temporary winter seal, installing plastic window film kits (3M makes effective versions for $8-15 per window), or adding heavy curtains or cellular blinds for an extra insulation barrier. These measures can reduce heat loss by 10-25% according to Natural Resources Canada.

Ottawa-specific considerations include our extreme temperature swings that cause significant expansion and contraction in window materials. Older homes in areas like the Glebe or Centretown often have original wood windows that may need professional restoration rather than simple weatherstripping. Heritage district properties may have restrictions on window modifications.

If you're finding drafts around the entire window frame or the window itself is warped, this typically indicates the window needs professional attention or replacement. Safety note: Working on upper-floor windows requires proper ladder safety or should be left to professionals.

Next steps: Start with the candle test to identify draft sources, then tackle weatherstripping and caulking during mild weather. If the window still feels drafty after these measures, or if you notice condensation between double-pane glass, it's time to consult a window professional for assessment and potential replacement quotes.