Drafty windows and doors can account for 25-30% of your heating and cooling energy loss. Weatherproofing is one of the highest-ROI home improvements you can make — most projects cost under $50 and save hundreds per year.
Identifying Air Leaks
Before you start sealing, find where the leaks are:
- Candle or incense test — on a windy day, slowly move a lit candle or incense stick around window and door frames. Flickering or smoke movement indicates air infiltration
- Hand test — on cold days, feel around frames for cold air movement
- Visual inspection — look for daylight around door frames, cracked caulk, compressed weatherstripping, and gaps where different materials meet
Window Weatherproofing
Caulking (exterior):
- Remove old, cracked caulk completely before applying new
- Use silicone or polyurethane caulk for exterior applications — they’re flexible and weather-resistant
- Apply when temperatures are above 40°F for proper adhesion
- Seal where the window frame meets the siding/trim
Weatherstripping (between sash and frame):
- V-strip (tension seal) is the most durable option for double-hung windows
- Foam tape is the cheapest but least durable — plan to replace annually
- Felt is inexpensive but compresses quickly and isn’t moisture-resistant
Window film (interior):
- Heat-shrink plastic film kits create a dead air space that improves insulation
- Most effective for single-pane windows in cold climates
- Apply in fall, remove in spring
- Won’t work on windows you need to open
Door Weatherproofing
Door sweeps:
- Install on the bottom of exterior doors to seal the gap with the threshold
- Choose adjustable sweeps for uneven thresholds
- Don’t forget the garage-to-house door
Weatherstripping (door frame):
- Magnetic weatherstripping provides the tightest seal for metal doors
- Compression weatherstripping (foam or rubber) works well for wood doors
- Replace when weatherstripping no longer makes firm contact with the door when closed
Threshold adjustment:
- Many thresholds have adjustment screws — tighten to close gaps with the door sweep
- If the threshold is worn or damaged, replacement is straightforward
Climate-Specific Priorities
Cold climates: Focus on thermal barriers. Double-pane windows, storm windows, and interior window film provide the biggest energy savings. Air sealing is critical.
Hot, humid climates: Focus on keeping conditioned air in AND moisture out. Seal exterior penetrations thoroughly. Consider Low-E window film to block solar heat gain.
Wind-prone areas: Weatherproofing serves double duty — energy efficiency and wind-driven rain protection. Use high-quality exterior caulk and ensure proper flashing above windows and doors.
ROI Expectations
- Caulking and weatherstripping: $20-50 in materials can save $100-300/year in energy costs. Payback in weeks
- Window film kits: $5-10 per window, saves $10-30 per window annually
- Storm windows: $75-200 each, save $25-50 per window annually. 3-5 year payback
Related Reading
- Best Weatherstripping Products
- Home Insulation Guide by Climate Zone
- Energy Efficiency Tips by Region
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