Repair or replace windows?

Whether to repair or replace windows comes down to the frame. If the frame is sound, most faults are cheap to fix: a misted unit, a stiff hinge, a broken handle or a worn seal. If the frame is rotten, warped or cracked, repairs only buy time, and replacement is usually the better money.

Faults that are worth repairing

These are common on windows of any age, and none of them needs a new window:

• Misted glass. A new sealed unit fits the old frame. It typically costs £90 per unit, against £5,000 for a whole house of new uPVC windows. See misted double glazing.
• Stiff or dropped sashes. Usually the friction hinges are worn. They’re standard parts and quick to change.
• Broken handles and locks. Most uPVC hardware is replaceable. A locksmith or window repairer can match it.
• Draughts round the opening. The rubber gaskets perish. New gaskets cost little and restore the seal.
• Rattling timber sashes. A specialist can overhaul and draught-proof original sash windows, keeping their character.

Signs a window needs replacing

Repairs stop making sense when the frame itself has failed. Look for:

• soft, rotten timber at the sill or the bottom rail, which a screwdriver sinks into;
• uPVC that has warped, so the sash no longer closes evenly;
• condensation streaming down the inside of single glazing all winter;
• several failed units and worn hardware in the same window;
• windows that don’t open far enough to escape through in a fire.

In addition, if you’re replacing most of the windows anyway, doing them all at once usually brings the price per window down.

Repair or replace windows: comparing the cost

Job	Typical price
Replacement glass unit	£90 per unit
uPVC windows, whole house	£5,000
Sash windows, per window	£900
Secondary glazing, per window	£280

Prices include VAT and come from our product pages, which break each one down.

Period windows are a special case

Original sash and casement windows on a period house are often worth repairing even when they look tired, because replacements that look right cost far more. In a conservation area or on a listed building, the council may expect you to repair them. Secondary glazing then adds warmth and quiet without touching the original. See listed building windows.

How to decide whether to repair or replace windows

Get a repair quote and a replacement quote for the worst windows, then compare them over the years you expect to stay. If the house is listed or in a conservation area, check the Planning Portal’s guidance on windows before choosing. When you’re ready, get quotes from local installers.