Window repair cost

Repairing a window costs $150 to $700, typically around $350. Replacing it costs $450 to $2,500. That gap is why it is worth knowing which faults are repairable, and the answer is more of them than the replacement industry suggests.

The single most common reason people replace windows is a foggy double-glazed unit, and that is usually repairable for a quarter of the price.

What it costs

The foggy window

Condensation between the panes means the seal on the insulated glass unit has failed and the inert gas has escaped. The window still keeps rain out. It has lost most of its insulating benefit and it looks bad.

You do not need a new window. You need a new insulated glass unit, which is the glass sandwich that sits inside the existing frame and sash.

A glazier measures the sash, orders the unit, and swaps it. It costs $200 to $600 per sash against $450 to $2,500 for a whole new window, and the frame, the trim and the interior finish are untouched.

Where this does not work: the sash is a discontinued profile nobody can glaze, the frame itself is rotten or distorted, or the window is a fixed unit glazed into the frame at the factory. Ask a glazier rather than a window company, because a window company sells windows.

Repair when

• The glass has fogged and the frame is sound
• A single pane has cracked
• The window will not stay up, which is a balance or a cord, not a window
• A casement will not crank, which is a $150 operator
• It is drafty, which is usually weatherstripping and caulk
• The exterior finish is failing on a wood window that is otherwise solid

Replace when

• The frame is rotten, distorted or racked out of square
• It is a single-glazed window in a cold climate and you are staying
• The window will not lock, and the sash cannot be adjusted to meet the frame
• Repairs have become annual
• You are re-siding, which is the one moment the flashing can be integrated properly

That last one is worth planning around. Replacing windows during a re-side lets the window flashing tie into the house wrap correctly. Doing them years apart guarantees a compromise at every opening, and window leaks almost always start at the head flashing.

The efficiency argument, honestly

Replacing single-glazed windows with modern double glazing in a cold climate saves real money: typically 10 to 20% of heating cost across a whole house.

Replacing serviceable double glazing with better double glazing saves very little, usually 2 to 5%, and takes decades to pay back. The industry sells the second as though it were the first.

Cheaper things that do more for a drafty window: weatherstripping, caulking the exterior perimeter, an interior storm panel, and heavy curtains. A hundred dollars a window against a thousand.

Frequently asked questions

Can a foggy window be defogged rather than reglazed?

There is a service that drills the unit, cleans it and fits a breather valve. It removes the visible fog and does not restore the gas fill or the seal. It is cheap and it is a cosmetic fix; if the appearance is the whole problem, it is reasonable.

Is a failed seal covered by warranty?

Often, if the window is under 10 to 20 years old and you have the paperwork. Glass warranties are common and frequently unclaimed because nobody looks. Find the manufacturer's mark, usually etched in a corner of the glass, before paying.

How long do windows last?

Vinyl 20 to 40 years, fiberglass 30 to 50, wood 30 to 100 with maintenance, aluminum 30 to 50. The insulated glass seal is the shortest-lived component at 15 to 25 years, and it is replaceable.

Should I replace all the windows at once?

Financially, no. Doing them in phases as they fail costs a little more per window and spreads the money. The exception is a whole-house re-side or a house full of single-glazing in a cold climate.

Why is my new window still drafty?

Almost always the installation rather than the window: gaps not insulated, no backer rod and sealant at the perimeter, or the sash not adjusted to compress the seal. All three are the installer's to fix and worth raising while the job is fresh.