How To Fix a Drafty Window: 5 Methods To Try

Not only can drafty windows spike your energy bill, but they can also make your house feel downright uncomfortable. Fortunately, a drafty window typically doesn’t require full window replacement, said Constantine Anest, owner of Ethos Roofing & Restoration in Denver.

“Drafty windows are often caused by gaps or cracks in the window frame, worn-out weather stripping, or damaged seals,” Anest explained. “Fluctuating temperatures, poor installation, or settling of the home often lead to shifting of the window frames, which is the cause of drafts entering.”

In many cases, sealing drafts requires only caulk or new weather stripping. But if the glass is cracked or the frame is warped, you may need professional repairs, or even a full replacement, to fix the root of the problem.

How To Pinpoint Where the Draft Is Coming From

Sometimes, finding a draft is as easy as running your hand around the window and feeling a breeze. Other times, it’s trickier to pinpoint. If you suspect a window is drafty but aren’t sure, try one of these quick tests:

• Candle test: Light a candle and slowly move it around the window frame. If the flame flickers, you’ve found your draft.
• Tissue test: Tie a tissue to a string and move it around the window. If the tissue moves, take note — this is likely where air is entering.

Most drafts come from small gaps around the window frame. However, drafts can also result from seal failure, which is the breakdown of the airtight seal that holds insulating gas between double- or triple-pane windows. Signs of a window seal failure include fogging or condensation between the window panes. In more obvious cases, the draft is coming from a visible crack in the glass or window frame.

Methods To Fix a Drafty Window

There are several ways to fix a drafty window. What you choose should depend on the type of draft and its cause. In some cases, you’ll need to consult a window professional or even consider replacement.

Depending on the cause of the air leak, you may only need a few supplies and less than an hour to remedy the problem.

Common supplies for fixing a drafty window:

• Foam backer rod
• Window caulking
• Weather stripping
• Window insulation film (optional)

Treat Large Gaps Around the Frame With Gap Filler (If Necessary)

If the gap around your window is wide enough to fit a finger, insert a foam backer rod before caulking. Foam backer rods are used to fill crevices in many construction applications. They’re inexpensive and available in various sizes.

This improves insulation and provides a better surface for the caulk to adhere to.

Caulk Around the Windows

Caulking seals your window’s perimeter, blocking pesky drafts from sneaking in around the trim. Before applying caulk, make sure the window, trim, and surrounding wall are clean and free of dust.

Apply a bead of nontoxic interior latex caulk where the window meets the wall. For outdoor gaps, use exterior-grade caulk to seal around the outside of the window as needed.

Apply Weather Stripping

While caulk is best for sealing gaps around the window frame, weather stripping helps block drafts where the window opens and closes — and it helps provide a tight seal when the window is shut. Two of the most common types of weather stripping for windows are V-strip and adhesive-backed foam.

To install weather stripping on a double-hung window (the most common window type):

• Thoroughly clean the window sash and frame.
• Apply V-stripping along the sides of the window where the sash slides up and down.
• Apply adhesive foam tape to the bottom edge of the sash where it meets the sill when the sash is closed.

Call In a Professional if the Window Seal or Glass Is Damaged

Unfortunately, fixing window glass is not a DIY-friendly job. If the seal of your window is broken or there’s a crack in the glass, you will need to have it professionally repaired or replaced.

In general, single-pane windows with small cracks can be repaired, while double- or triple-pane windows with broken or cracked glass call for the replacement of the insulated glass unit or a full window replacement, depending on the window type and manufacturer.

Apply Window Film

To further reduce drafts and retain heat in the winter, consider installing window insulation film. Window insulation kits include clear plastic sheets and double-sided tape.

To install, apply the tape around the window frame, attach the plastic, then use a hair dryer to shrink the film and remove wrinkles or slack.

How Much Does It Cost To Fix a Drafty Window?

Window repair costs vary widely, depending on the cause of the draft. “Typically, it costs between $100 and $300, depending on the severity of the issue and whether it’s a simple seal replacement or a more involved repair, such as recaulking or weather stripping,” Anest said.

The average cost to fix broken window glass is around $300–$700, and if you need a full window replacement, expect to pay anywhere from $400 to $1,000, depending on the window’s size, type, and frame material.

Repairing Vs. Replacing Drafty Windows

Opt for repair if the weather stripping around your window is worn or damaged, there are small gaps easily filled by caulk, or there’s cracked glass in a single-pane window.

“Repairing a drafty window is ideal if the frame and glass are in good condition and the draft is coming from a seal, weather stripping, or a minor gap,” Anest said.

But if your windows are over 20 years old, there is major warping or rotting at the frame, or your draft-stopping attempts haven’t worked, it’s time for new windows.

Use the following table as a general guide on when to repair versus replace a drafty window.

Maintaining Your Windows

Routine maintenance is the best way to keep windows efficient and prevent future drafts. Keep up with these few simple tasks:

• Regularly wash the interior and exterior of your windows, including the window tracks.
• Inspect the windows once or twice a year, looking for damaged weather stripping or missing caulk.
• Make small repairs as soon as you see them.

Next Steps

If you’ve sealed gaps and replaced weather stripping but still feel a draft, it’s time to call a pro. While minor fixes are DIY-friendly, persistent drafts may indicate frame issues or that it’s time for a full window replacement.

Consult a local window contractor for help pinpointing the problem. If replacement is needed, start researching top window brands to find the frame type, style, and price range that fits your home and budget.