How to Weatherstrip a Door and Stop Drafts for Good

Hold your hand by an exterior door on a cold, windy day. If you feel air moving, you are paying to heat the outdoors. Weatherstripping is one of the cheapest energy upgrades there is, and most doors take under an hour. Start with a test that shows exactly where the air gets in.

Why bother?

The US Department of Energy recommends air sealing (caulking and weatherstripping) as one of the most cost-effective ways to cut heating and cooling bills and make a home more comfortable. The DOE's consumer guide notes caulking and weatherstripping often pay for themselves within about a year, and ENERGY STAR promotes sealing and insulating as a core way to cut heating and cooling costs. Doors are an easy place to start because the gaps are visible and the materials are inexpensive.

Find the leaks

• Daylight test: on a sunny day, close the door and look for light around the edges and threshold.
• Paper test: close the door on a sheet of paper. If it slides out easily, the seal is too loose at that spot. Test all the way around.
• Incense or candle test: on a windy day, slowly move a stick of incense around the frame. Wavering smoke means a draft. Keep flames away from curtains.

Choose the right weatherstripping

• Adhesive foam tape: cheap and easy; compresses well; lasts a few seasons. Good for quick fixes and irregular gaps.
• V-strip (tension seal): vinyl or metal folded into a V that springs open to seal; durable and invisible when the door is closed. Good for the sides of a door jamb.
• Kerf-in weatherstripping: fits into the slot in many modern pre-hung door frames; replace with a matching profile.
• Tubular rubber or silicone gasket: very effective; nail-on or screw-on versions.
• Door sweep: strip attached to the bottom of the door to close the gap at the threshold.
• Door shoe or threshold gasket: wraps the bottom of the door or replaces the threshold insert.

Check the door frame first. If you see a slot holding a foam-filled rubber strip, buy a matching kerf-in replacement; it simply presses in.

Tools and materials

• Weatherstripping and door sweep sized for your door
• Tape measure, utility knife, scissors
• Screwdriver or drill, small nails/hammer if required
• Rubbing alcohol and a rag

Installation: sides and top

1. Remove old weatherstripping and scrape off adhesive.
2. Clean the jamb with rubbing alcohol and let it dry; adhesive will not stick to dust or grease.
3. Measure each side and the top, and cut strips to length.
4. Install the top piece first, then the sides, butting the ends tightly at the corners.
5. For adhesive foam: peel and press firmly as you go. For V-strip: position it so the V opens toward the outside, nail or stick it in place.
6. Close the door. It should latch with slight resistance. If it is too hard to close, use thinner material.

Installation: door sweep

1. Close the door and measure the width.
2. Cut the sweep to length with a hacksaw (metal) or utility knife (vinyl).
3. Hold it against the inside face of the door so the flexible edge just touches the threshold.
4. Mark and drill pilot holes, then screw it on. Slotted holes let you adjust height.
5. Open and close the door: the sweep should touch lightly without dragging hard on rugs.

Door draft checklist

• Daylight or paper test done around the door
• Old weatherstripping removed and surface cleaned
• Top and side strips installed, corners tight
• Door sweep or threshold seal installed
• Door latches without excessive force
• Repeat paper test: snug all the way around

Do not forget these leaks

The DOE's air sealing guide lists common leak spots beyond doors: windows, attic hatches, plumbing and wiring penetrations, recessed lights and the gap where walls meet the foundation. Foam gaskets behind outlet and switch plates on exterior walls are a quick extra fix.

How long does weatherstripping last?

Foam tape may need replacing every year or two; vinyl, silicone and metal products often last many years. Check each fall with the paper test.

Fixing the door itself first

Weatherstripping cannot seal a door that does not close properly. Before buying materials, check:

• Sagging door: if the gap is wider at the top of the latch side, the hinges may be loose. Replace one short screw in the top hinge with a 3-inch screw that reaches the framing stud; this often pulls the door back into square.
• Strike plate: if the door rattles when latched, the strike plate may sit too far from the stop. Many strike plates have an adjustable tab you can bend slightly inward with a screwdriver so the door pulls tighter against the weatherstripping.
• Warped door: a door that bows can leave a gap in the middle of the latch side. Thicker compressible weatherstripping in that section may compensate; badly warped doors may need replacing.

Storm doors and sliding doors

Storm doors add an extra air layer and their own sweeps; check that the closer is adjusted so the door shuts fully. Sliding patio doors use pile weatherstripping (brush-like strips) in tracks on the panel edges. Replacement pile is sold by width and pile height; take a sample to the store. Clean the bottom track regularly, as grit stops the panel from closing tightly.

Comfort benefits beyond the bill

Drafts make rooms feel colder than the thermostat reading because moving air carries heat away from skin. Sealing a drafty entry can make the nearby living space comfortable without turning up the heat, and it also reduces outdoor noise, dust and insects getting in.