Weather stripping seals the gaps around your window frame where air leaks out and drafts come in

Window weather stripping is a foam, rubber, or felt strip that you stick or nail around the inside edge of your window frame to block air movement. It costs between $1 and $5 per window and takes 15 to 30 minutes to install. You do not need special tools—a utility knife, measuring tape, and a caulk gun (if you choose adhesive-backed strips) are enough.

The most common types are self-adhesive foam tape, which peels and sticks; rubber or silicone strips, which last longer but require small nails; and felt strips, which are cheapest but wear out fastest. All three work the same way: they fill the space between the moving sash (the part that slides) and the fixed frame so air cannot pass through.

Key Takeaways

  • Measure the perimeter of your window frame before buying weather stripping, because different windows need different lengths.
  • Clean the frame with a dry cloth or rubbing alcohol to remove dust and old adhesive, or the new strip will not stick.
  • Self-adhesive foam tape is the easiest for renters and first-timers; rubber strips with nails last longer but require small holes in the frame.
  • Install strips on the sides and top of the frame where the sash closes, not on the sill (the bottom), which needs to drain water.

Measure your window frame before you buy

Measure the height of both side jambs (the vertical pieces on the left and right), the width of the head jamb (the top horizontal piece), and the width of the sill (the bottom). Write these down. Most windows need stripping on three sides: both sides and the top. The sill usually does not get stripping because water needs to drain out, not be sealed in.

Add the three measurements together to find the total length you need. If your window is 36 inches wide and 48 inches tall, you need roughly 36 + 48 + 48 = 132 inches, or about 11 feet. Buy a roll or kit that covers at least that much—most come in 10-, 17-, or 20-foot lengths. If you have multiple windows, measure each one separately; they are rarely the same size.

Clean the frame so the adhesive sticks

Dust, paint chips, and old weather stripping prevent new strips from bonding. Use a dry cloth or old toothbrush to wipe the inside edge of the frame where the strip will go. If the frame is sticky or has old adhesive residue, dampen a cloth with rubbing alcohol and wipe it down, then let it dry completely—this usually takes 5 to 10 minutes.

Pay special attention to the corners and the groove where the sash slides. If you find old stripping still attached, peel it off. If it will not come off cleanly, use a plastic scraper or old credit card to lift the edge, then rub the residue away with alcohol. Do not use a metal scraper on wood frames, as it will gouge them.

Install self-adhesive foam tape on the frame

Self-adhesive foam is the easiest method for most homeowners. Start at the top of the frame. Peel back 2 to 3 inches of the backing and press the strip firmly into the corner, then slowly peel the backing as you press the strip down the length of the frame. Use your thumb or a plastic roller to press it flat every few inches so it bonds evenly.

Do the left side next, then the right side. At the corners, overlap the strips slightly or cut them at a 45-degree angle so they meet neatly. Do not stretch the foam as you install it—let it sit naturally in the frame. Once all three sides are done, close the window slowly. The sash should meet slight resistance as it compresses the foam. If it is too tight, you may have installed the strip too far into the frame; if it is too loose, the strip may not be pressed down firmly enough.

Use rubber or silicone strips with nails for longer-lasting seals

Rubber and silicone strips last 5 to 10 years, compared to 2 to 3 years for foam. They require small finishing nails (typically 1 to 1.5 inches long) spaced every 4 to 6 inches. Start at one corner and drive a nail through the strip into the frame, then move along the length, nailing every 4 to 6 inches. Use a hammer and tap gently—you only need to drive the nail far enough to hold the strip, not flush with the surface.

Rubber strips are thicker than foam, so check that your window still closes smoothly after installation. If the sash binds (sticks or resists closing), the strip may be too thick for that window. Some rubber strips come with a groove on one side that fits over a small lip on the frame, which holds them in place without nails—check your product instructions to see if yours does.

Test the seal and replace strips every few years

Close the window and run your hand around the inside edge of the frame. You should feel no draft. If you do, the strip may not be pressed down firmly, or it may have shifted during installation. Open the window and press it down again, or peel it back and reposition it.

Foam strips typically last 2 to 3 years before they compress and stop sealing. Rubber and silicone last longer but eventually crack or harden. Check your strips each fall before heating season. If you see gaps, cracks, or if the foam no longer springs back when you press it, replace that side or the whole window. Replacement is the same process: peel off the old strip, clean the frame, and install new stripping.

Frequently Asked Questions

Can I install weather stripping on a window that is painted shut?

No. A painted-shut window cannot open, so you cannot test the seal or adjust it if it is too tight. Have the window unstuck first by carefully running a utility knife around the paint line, then gently tapping the sash with a rubber mallet. Once it moves freely, install the stripping.

What if my window frame is metal instead of wood?

Self-adhesive foam works on metal, but clean it thoroughly with rubbing alcohol first because metal is often dusty or oily. Rubber strips with nails do not work well on metal frames because the nails do not hold securely. Stick with adhesive-backed strips for metal windows.

Do I need to remove the window sash to install weather stripping?

No. You install the stripping around the frame while the sash is in place. You only need to open and close the window to test the seal. Removing the sash is not necessary and makes the job harder.

Will weather stripping stop all drafts around my window?

Weather stripping seals the gaps where the sash meets the frame, but it does not fix drafts that come through cracks in the glass, gaps between the frame and the wall, or damaged caulk on the outside. If you still feel cold air after installing stripping, the problem may be outside the frame or in the glass itself.

Can I use weather stripping on a sliding glass door?

Yes. Measure and install it the same way—on the sides and top where the door closes. Do not put it on the sill at the bottom, as water needs to drain. Sliding glass doors often have a threshold (a raised piece at the bottom) that already blocks most air, so focus on the sides and top first.