Repair or Replace Windows? A Decision Guide by Symptom

Many window problems can be repaired: a fogged glass unit can be replaced in the old sash, a worn sash or balance can be swapped, and drafts often come from weatherstripping that costs little to renew. Replacement usually makes more sense when the frame itself is rotted or warped, when several problems show up in the same window at once, or when the windows are single-pane and you want better insulation. The symptom tells you which side of that line you are on.

On cost, repairs are usually far cheaper per window. HomeGuide reports $175 to $600 for most window repairs, against $400 to $2,000 when a window is beyond repair (February 5, 2026) ¹. HomeAdvisor reports an average of $400 for window repairs, compared with $850 for a full replacement (updated June 17, 2026) ². The decision table below matches each symptom to the repair that addresses it.

How to think about the choice

A window has three main parts: the frame fixed in the wall, the sash that holds the glass and moves, and the sealed glass unit inside the sash. Hardware, balances and weatherstripping attach to these. A problem in a part that can be swapped is usually a repair. A problem in the frame, or one that comes back after repair, points to replacement.

Pella's FAQ puts it the same way: hardware problems, worn weatherstripping or a single cracked pane may be repairable, while a damaged or rotting frame, a failed seal between panes, or a window failing on several counts typically calls for replacement ⁹. Pella sells replacement windows, so read that as a manufacturer's view; replacing a failed glass unit in its existing sash is a common repair with its own survey prices, shown below.

Decision table by symptom

All ranges are HomeGuide's (February 5, 2026, for repairs ¹; October 15, 2025, for sash replacement ⁴) or HomeAdvisor's (updated June 17, 2026 ²), as marked. They are national ranges for one window; your quote will depend on size, access, glass type and local labor.

Fogged or foggy glass

Moisture that forms between the two panes of an insulated window means the seal around the glass unit has failed. Condensation on the inside or outside surface is different and usually comes from indoor humidity; Pella's FAQ draws the same line ⁹. The window condensation article covers the surface kind.

A failed seal does not mean the whole window has to go. The sealed glass unit can usually be replaced in the existing sash. Angi reports a national average of $285 per window for glass replacement, with most homeowners paying $181 to $414, based on 13,612 projects (updated September 17, 2026) ³. HomeGuide reports $150 to $500 for glass replacement in its repair table ¹. The difference comes from method and what is counted: Angi's figure is drawn from projects reported by its pros, HomeGuide's from research and costs reported by its members ^{1 3}. The window glass replacement cost article goes into detail.

Check the warranty first. Andersen, for example, warrants its 400 Series and 200 Series glass against seal failure that causes obstruction of vision for 20 years from purchase, though labor is not included when it supplies replacement glass ¹⁰.

Drafts and air leaks

Drafts often come from worn weatherstripping, a latch that no longer pulls the sash tight, or gaps where the window meets the wall. The U.S. Department of Energy lists weatherstripping doors and windows and caulking air leaks among the first steps in weatherizing a home, and estimates that sealing uncontrolled air leaks can save 10% to 20% on heating and cooling bills ⁸. That figure is for the whole house, not windows alone.

If new weatherstripping does not stop the draft, the sash or frame may be warped, and that is when replacement comes into the picture.

Sashes that stick, drop or will not close

A double-hung sash that slides down on its own usually has a failed balance or spring, among the lower-cost repairs in HomeGuide's table ¹. A sash that is rotted, cracked or warped can be replaced on its own while the frame stays, provided the frame is sound. The window sash replacement article explains when that works and who sells replacement sashes.

Rot

Rot in the sash only is a repair job: a new sash goes into the old frame. Rot in the frame or sill is more serious, because the frame is what seals the window to the wall. HomeGuide puts frame repair at $150 to $600 and notes that simple repairs include patching holes or filling small cracks, while rotted window frames are typically replaced rather than repaired ¹. A full-frame replacement also lets the installer see and fix water damage in the opening, which HomeAdvisor lists as one of its advantages ².

Single-pane windows

Single-pane windows are not broken, but they insulate poorly. There are two paths. The Department of Energy says that replacing single-pane windows with double-pane windows that have high-performance glass may be cost effective, but that exterior storm windows are an alternative ⁸. DOE also estimates that low-e storm windows can save 10% to 30% on heating and cooling costs, depending on the type of window already installed ⁸. The storm windows article covers what they are and how they fit.

Older homes and lead paint

Many older wood windows were painted with lead-based paint. The EPA's lead Renovation, Repair and Painting (RRP) rule applies to window work in pre-1978 housing unless it has been determined that the components affected do not contain lead-based paint at or above the levels the rule sets, and that determination has to be made by an inspector, risk assessor or renovator holding EPA credentials, using an EPA-recognized test kit or paint chip sampling ¹¹. Read the EPA's answer on window work in pre-1978 homes and ask any company that will work on old windows how it follows the rule.

Rules of thumb, and their limits

HomeGuide offers a general rule: replace rather than repair when a window is more than 15 years old, is in poor condition, or when repairs cost more than half the price of a new window ¹. That is one publisher's rule, not a standard, and a 15-year-old window with one failed seal may still be worth repairing.

A fairer test compares the repair quote with a replacement quote for the same window. Per-window replacement figures differ by survey: HomeGuide reports $450 to $1,500 for a single-hung window in a basic aluminum or vinyl frame, installed (February 5, 2026) ⁵, Fixr about $800 on average with a typical $450 to $1,200 (updated January 21, 2026) ⁷, and Angi about $750 per window within a whole-house average of $7,348 from 17,857 projects (updated October 15, 2026) ⁶. The surveys use different data and dates, which is why they do not match. The window replacement cost guide sets them side by side.

Replacement tends to win when:

• the frame is rotted, warped or out of square;
• several windows show the same failure, or one window has more than one problem;
• parts for the window are no longer made;
• you want a different style, size or frame material.

Repair tends to win when:

• the frame is sound and only one part has failed;
• the windows are covered by a warranty for that part;
• the windows match the house's style and replacing them would change its look.

How long windows last

Age alone is a weak signal. Lifespan depends on the material, the climate, how the window was installed and how it was looked after, and manufacturers state different ranges for different materials. The how long do windows last article lists them by source.

Getting it assessed

Ask for two kinds of quote: one to repair, one to replace. A company that only sells new windows may not offer repair, and a glass shop may not quote a full replacement, so it can help to ask one of each. Ask each company what caused the problem, whether the frame is sound, and whether the work affects any remaining warranty. Is the installer licensed where you live? The how to choose a window installer guide lists what to check.

If replacement is on the table, compare quotes from window installers to see what a new window would cost for your house.

We are not affiliated with the manufacturers named.

About these figures

• ¹ Reported: HomeGuide window repair costs by repair type, repair vs. replacement range, glass replacement, frame repair and its replace-or-repair rule of thumb, dated February 5, 2026, checked October 22, 2026.
• ² Reported: HomeAdvisor average repair ($400) vs. replacement ($850), small-crack repair figure and full-frame advantages, updated June 17, 2026, checked October 22, 2026.
• ³ Reported: Angi national average and typical range for window glass replacement and project count, updated September 17, 2026, checked October 22, 2026.
• ⁴ Reported: HomeGuide window sash replacement cost per window, dated October 15, 2025, checked October 22, 2026.
• ⁵ Reported: HomeGuide installed per-window replacement range for single-hung windows in basic frames, dated February 5, 2026, checked October 22, 2026.
• ⁶ Reported: Angi per-window and whole-project replacement averages and project count, updated October 15, 2026, checked October 22, 2026.
• ⁷ Reported: Fixr per-window replacement average and typical range, updated January 21, 2026, checked October 22, 2026.
• ⁸ Official record: DOE Energy Saver Guide on weatherstripping, air sealing (10% to 20% estimate), storm windows (10% to 30% estimate) and replacing single-pane windows, checked October 22, 2026.
• ⁹ Reported: Pella FAQ on which window problems may be repairable and on condensation between panes, checked October 22, 2026.
• ¹⁰ Reported: Andersen 400 Series and 200 Series limited warranty glass and seal terms and labor exclusion, revised September 8, 2023, checked October 22, 2026.
• ¹¹ Official record: EPA answer on when the RRP rule applies to window work in pre-1978 housing, page last updated October 15, 2026, checked October 22, 2026.