How to Replace Weatherstripping on Windows

A drafty window costs you about $200 a year in wasted heating and cooling, makes your space uncomfortable in every season, and announces itself every time you walk past with a hand held up to check for the breeze. Replacing weatherstripping is a $20 fix that takes less than an hour per window and works immediately — no curing time, no waiting for caulk to dry, just press it on and the draft stops.

Most weatherstripping fails after 3–5 years of temperature swings and UV exposure. If you can feel air movement when you hold your hand near a closed window, or if the old seal looks compressed, cracked, or peeling, it’s time to replace it. Renters: this is almost always deposit-safe and reversible.

What you’ll need

Tools:

Utility knife or scissors
Tape measure
Putty knife or old credit card
Rubbing alcohol and clean rag
Hair dryer (optional, for adhesive removal)

Materials:

Weatherstripping (type depends on your window — see below)
Weatherstripping for one standard double-hung window costs $8–$15

Prerequisites:

Window opens and closes smoothly
Frame is clean and dry

Understanding window weatherstripping types

Before you buy, know which type fits your window.

Foam tape is the easiest install — peel-and-stick with an adhesive backing. It costs $6–$10 per roll, lasts 1–3 years, and works on any flat surface where compression creates the seal. 3M weatherstripping foam tape is widely available and forgiving in moderate climates.

V-strip (also called tension seal) is a folded piece of vinyl or metal that springs open to fill gaps. It’s more durable than foam — 3–7 years — and costs $10–$18 per window. Frost King V-Seal is a solid mid-range option. V-strip fits into channels, so it works well on double-hung and sliding windows where you need a seal that won’t interfere with operation.

Kerf-style weatherstripping is the factory-installed type on most newer windows — a barbed strip that slots into a groove in the sash. If your old strip pulled out of a kerf slot, buy the replacement from the window manufacturer or use Schlegel Q-Lon, which fits most kerf channels. This is the longest-lasting type (7–10 years) but requires an existing kerf groove.

Felt weatherstripping is cheap ($4–$8) and old-school. It’s not adhesive-backed, so you’ll need to staple or tack it. It works, but it absorbs moisture, collects dust, and wears out fast. Use it only if you’re in a very dry climate or need a temporary fix.

Foam vs. V-strip weatherstripping: Foam is faster to install and more forgiving on irregular surfaces. V-strip lasts longer, handles friction better on moving parts, and stays effective in extreme cold. If you’re sealing a window that doesn’t open often, foam is fine. If it’s a window you open and close regularly, V-strip is worth the extra ten minutes of install time.

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How to seal drafty windows: step-by-step

Step 1: Remove old weatherstripping

Open the window fully. Peel off the old weatherstripping by hand — most adhesive-backed types come off in one pull. If it’s stuck or leaves residue, warm it with a hair dryer for 20 seconds, then scrape gently with a putty knife or old credit card. Don’t gouge the paint; you’re just loosening adhesive.

For kerf-style weatherstripping, grip the strip near one end and pull straight out of the channel. It should release without tools.

Step 2: Clean the frame

Wipe the entire contact surface with rubbing alcohol on a clean rag. You’re removing dust, old adhesive, oils, and anything else that’ll prevent the new strip from sticking. Let it dry completely — two minutes is enough.

This step matters more than people think. I’ve watched foam weatherstripping peel off within a week because someone skipped the cleaning step and pressed it onto a dusty frame.

Step 3: Measure and cut

Measure each side of the window frame where you’ll apply weatherstripping. For double-hung windows, that’s usually the top and both sides of the lower sash, and the bottom of the upper sash. Add an extra inch to each measurement so you have room to adjust, then cut your weatherstripping to length with scissors or a utility knife.

For V-strip, fold it lengthwise before measuring so you’re working with the actual installed shape.

Step 4: Apply the weatherstripping

For foam tape: Peel back 2–3 inches of the backing, press the end into place at one corner, then slowly peel and press as you move along the frame. Keep it straight and avoid stretching — stretched foam leaves gaps when it relaxes.

For V-strip: Open the fold slightly and press the adhesive edge into the channel or frame. The fold should face the direction the window closes from, so it compresses when the sash meets it. If your V-strip isn’t adhesive-backed, use small brads every 4–6 inches.

For kerf-style: Push the barbed edge into the kerf slot with your thumb, starting at one end. Work your way along until the full strip is seated. It should click or snap into place.

Step 5: Test the seal

Close the window firmly and check for resistance — you should feel slight compression as it meets the new weatherstripping. Run your hand along the edges while someone holds a flashlight on the other side; if you see light gaps, the seal isn’t complete. Open the window, adjust the strip, and retest.

If the window binds or won’t latch, you’ve used weatherstripping that’s too thick. Replace it with a thinner profile or compressed foam.

How to replace door weatherstripping

Door weatherstripping uses the same types but different placements. Door sweeps attach to the bottom of the door and drag slightly on the threshold to block drafts. The Frost King adjustable door sweep costs around $8 and installs with four screws — no need to remove the door.

For the sides and top of the door, use V-strip or kerf-style if there’s a channel. Foam works, but foot traffic and UV exposure near a door degrade it faster than on a window. Entry doors see more wear than interior doors, so plan to replace door weatherstripping every 2–3 years instead of 5.

Bifold doors need thin foam or brush weatherstripping on the edges where panels meet. Garage doors use bulb or T-shaped rubber seals on the bottom and kerf-style on the sides; buy these by door width from a garage door supplier, not a general hardware store.

Troubleshooting common issues

Problem: Weatherstripping peels off within days The surface wasn’t clean or dry. Remove the strip, clean with rubbing alcohol, wait for full evaporation, and reapply. In very cold weather, warm the adhesive slightly with a hair dryer after pressing it on — this activates the bond.

Problem: Window won’t close or latch The weatherstripping is too thick or installed in the wrong spot. If it’s foam, try a thinner profile (1/4″ instead of 3/8″). If it’s V-strip, make sure the fold opens away from the sash travel, not into it.

Problem: Still feeling a draft after install You’ve sealed the operable parts, but the draft is coming from the frame-to-wall gap. That’s a different fix — you’ll need to caulk the interior trim or add rope caulk in the gap. Weatherstripping only seals the moving parts of the window.

Problem: Old adhesive won’t come off Use Goo Gone or WD-40 on a rag, let it sit for one minute, then scrape with a plastic putty knife. Wipe with rubbing alcohol afterward so the new adhesive has a clean surface.

FAQ

How long does window weatherstripping last?

Foam lasts 1–3 years, V-strip lasts 3–7 years, and kerf-style lasts 7–10 years depending on UV exposure and how often you open the window. Replace it when you feel a draft or see visible cracks.

Can I use the same weatherstripping on doors and windows?

Yes, but doors need more durable materials. Foam works on windows, but V-strip or kerf-style holds up better on doors due to higher traffic and friction. Door sweeps are door-specific and won’t work on windows.

What’s the best weatherstripping for old windows?

Foam tape is the most forgiving for irregular frames on old windows. If the frame is uneven or painted over many times, foam compresses to fill gaps that rigid V-strip can’t. Just clean the surface well before applying.

Should I weatherstrip the entire window or just the bottom?

Weatherstrip every edge where the moving part meets the frame — top and sides of the lower sash, bottom of the upper sash on double-hung windows. Sealing only the bottom leaves the sides open and wastes your effort.

Once you’ve finished your windows, the same skills apply to How to Fix a Squeaky Door Hinge in 5 Minutes and other small fixes that make your space feel tighter and more intentional. If you’re comparing tools for the next project, best utility knife for home repairs covers what’s worth spending on. The energy savings add up — how to reduce your heating bill breaks down where the money goes and which fixes pay off fastest. And if you’re weatherproofing before winter with pets in mind, how to draft proof your home for pets covers floor-level gaps that humans miss but animals feel immediately.