Sash windows Cost Calculator

A fitted replacement sash window costs £600 to £3,500 depending on material and size. uPVC sash windows are cheapest at roughly £600–£1,200, double-glazed softwood timber sashes run £1,200–£2,500, and hardwood heritage sashes reach £1,800–£3,500. Repairing or refurbishing an existing sash window is usually 40–60% cheaper, typically £350–£1,200 per window. Expect a 20–30% premium in London and the South East.

Basic repairs such as a broken cord or sticking sash cost £70–£300 per window. Re-glazing and repainting runs £200–£500, and repairing rotten timber costs £400–£800. A full overhaul covering draught-proofing, new cords, pulleys and re-balancing is £350–£650, while a complete refurbishment with timber repairs and redecoration ranges £650–£1,200 per window.

Replacing a single sash window costs £600–£3,500 fitted. A typical 3-bed Victorian terrace with six windows costs £4,500–£18,000 for a full replacement depending on whether you choose uPVC, softwood or hardwood timber and the glazing specification. Full box-frame replacement costs more than swapping the sliding sashes alone, and replacement makes most sense when the original frame is rotten beyond economical repair.

Double-glazed timber sash windows cost £1,200–£2,500 per window fitted for softwood and £1,800–£3,500 for hardwood. uPVC double-glazed sash windows are cheaper at £600–£1,200. To keep original frames in a period property, slim-profile or vacuum double glazing retrofitted into the existing sashes costs roughly £600–£1,500 per window. Acoustic or low-E upgrades add a further 10–25%.