Weatherstripping is one of the cheapest, highest-impact home improvements you can make. The U.S. Department of Energy estimates that drafts from poorly sealed doors and windows account for 25–30% of heating and cooling energy use in a typical home. A $15 weatherstripping kit on a drafty door can pay for itself in a single month during winter.
This guide covers how to diagnose draft problems, choose the right weatherstripping material for each application, and install it correctly so it actually seals — and lasts more than one season.
How to Find Drafts
Before buying anything, identify where air is actually leaking:
- The candle or incense test: On a windy day, hold a lit candle or stick of incense near door and window edges. Flickering indicates airflow.
- The paper test: Close a door on a piece of paper. If you can pull the paper out without tearing, the seal is insufficient.
- Visual inspection: Open the door and look at existing weatherstripping. Compressed, cracked, or missing foam is an obvious replacement candidate.
- Daylight check: On a bright day, close a door in a dark room. Any daylight visible around the frame means air is getting through too.
Types of Weatherstripping: Which to Use Where
Best for: window sashes, sliding doors, irregular gaps. Inexpensive, easy to apply, compresses to fill varied gaps. Lifespan: 1–3 years.
Best for: sides of door frames, double-hung window channels. Durable spring metal or plastic that holds its shape under pressure. Lifespan: 5–10 years.
Best for: bottom of exterior doors. Seals the gap between door and threshold. Available in brush, rubber, and vinyl styles. Lifespan: 3–7 years.
Best for: doors with larger gaps at the bottom. Automatic drop-down seals create a tighter barrier and look more finished than standard sweeps. Lifespan: 5–10 years.
Best for: door stop molding on exterior doors. Compresses when door closes, creates an excellent seal. Nailed or stapled in place. Lifespan: 5–10 years.
Best for: high-use exterior doors in commercial applications or severe climates. Most durable option but requires precise installation. Lifespan: 15+ years.
Installing Door Weatherstripping (Foam or V-Strip)
- Remove old weatherstripping: Peel off foam tape or pull out stapled/nailed strips. Clean the surface with rubbing alcohol to remove adhesive residue.
- Measure each side: Measure the top and both sides of the door frame separately. Cut weatherstripping slightly longer than measured, then trim to fit.
- Install top strip first: Press or nail the top strip across the door header, compressing slightly against the door face.
- Install side strips: For foam tape, peel backing and press into the door stop. For V-strip, fold it so the open end faces outward (toward the outside of the door) and press or nail into the door stop channel.
- Test the seal: Close the door and check for visible gaps. Run your hand around the frame to feel for air movement.
Installing a Door Sweep
The bottom of exterior doors is one of the biggest sources of drafts, pests, and water infiltration. A door sweep is one of the most impactful weatherstripping upgrades you can make.
- Measure the width of the door at the bottom
- Cut the sweep to length with a hacksaw (for metal sweeps) or utility knife (for rubber/vinyl)
- Close the door and hold the sweep against the inside bottom edge — it should just touch the threshold without dragging
- Mark the screw hole positions with a pencil
- Pre-drill pilot holes and attach with the included screws
- Adjust height if needed — most sweeps have slotted holes for fine-tuning
For exterior doors that drag on the sweep: Choose an automatic (drop-down) door sweep that rises when the door opens and drops to seal when it closes. These cost more ($30–$80) but eliminate the friction problem entirely.
Window Weatherstripping
Double-hung windows lose air where the two sashes meet and where the sashes slide in their channels. Self-adhesive foam tape works well on the meeting rails (where the two sashes come together). V-strip works well in the channels where the sashes slide up and down.
For casement windows, foam tape applied to the window frame (not the sash) creates a compression seal when the window closes. Replace any deteriorated gaskets on casement window hardware as well.
Mistakes to Avoid
- Overstuffing the gap with foam tape — too thick a foam strip prevents the door from closing fully and can warp the door over time
- Applying foam tape to dirty surfaces — it will peel off within weeks
- Using indoor weatherstripping on exterior doors — it will degrade quickly from UV and moisture
- Ignoring the threshold — the door sweep seals the bottom of the door, but the threshold itself may also need adjustment or replacement
When to Call a Handyman
Most weatherstripping is a DIY-friendly project. Call a handyman when:
- The door itself is warped or off-plumb — no weatherstripping will seal a door that has moved significantly
- You need a whole-house weatherstripping audit and replacement done in a single day
- Door threshold adjustment or replacement is needed (involves removing the threshold and may require cutting)
- Window frames are damaged, swollen, or need planing to close properly
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