uPVC window cost by size and specification
uPVC window cost in London (supply and installation, double-glazed, standard white): Casement window (600mm × 900mm): £280–£450 supply; £380–£600 installed. Casement window (1,200mm × 1,200mm): £350–£600 supply; £480–£800 installed. Tilt-and-turn (1,000mm × 1,200mm): £400–£700 supply; £550–£900 installed. Bay window (2,400mm wide, 3-pane): £800–£1,400 supply; £1,200–£2,000 installed. Coloured uPVC (anthracite grey, black foil-wrap): add 15–25% to white uPVC prices above. Full house replacement — 3-bed semi-detached (10 windows, white uPVC, including scaffold): £4,000–£7,500 installed. Full house replacement with coloured uPVC (anthracite grey): £5,000–£9,000 installed. Premium uPVC brands include Rehau, Veka, Kommerling, and Deceuninck — these offer thicker multi-chamber profiles with better thermal performance and hardware durability than budget uPVC systems.
uPVC windows in London — where they are and aren't appropriate
uPVC windows are appropriate for mid-market residential replacement windows in non-conservation-area London properties. They are not appropriate for: conservation areas (most London planning authorities require timber or slim-profile aluminium where windows are visible from the public highway); listed buildings (LBC requires like-for-like timber replacement or secondary glazing — uPVC is never approved); Victorian terraces in the front elevation where original sash windows are a character-defining feature (even outside conservation areas, replacing original sashes with uPVC casements can harm resale value significantly). uPVC is the most common window material in London's outer boroughs (Croydon, Bexley, Havering, Hillingdon, Bromley) where non-conservation residential stock predominates. In inner boroughs with high conservation area coverage (Camden, Islington, Hackney, Kensington and Chelsea), uPVC installations are uncommon on front elevations.
FENSA registration and Building Regulations for uPVC windows
All replacement window installations in England — including uPVC — must comply with Building Regulations Part L (thermal performance) and Part K (opening window safety). FENSA registration: the installer must notify the local planning authority (LPA) of the installation as a self-certification under the Competent Person Scheme. The installer issues a FENSA certificate on completion — essential for property sale (solicitors routinely check for FENSA certificates on window replacements within the last 10 years). If the installer is not FENSA-registered, the homeowner must apply to the LPA for Building Control approval separately (£50–£150 fee). Thermal requirements: replacement windows must achieve a minimum U-value of 1.4 W/m²K for the overall window (centre-pane U-value of approximately 1.1 W/m²K is typical for standard A-rated double-glazed uPVC). Safety glass: any replacement window in a critical location (within 800mm of floor level, within 300mm of a door, in a bathroom) must use toughened or laminated safety glass — a Building Regulations requirement.
uPVC window lifespan and maintenance
Modern uPVC windows from reputable manufacturers (Rehau, Veka, Kommerling) have a lifespan of 25–35 years before the frame profile begins to yellow, warp or lose rigidity. Sealed unit failure (condensation between panes) is the most common fault — typically occurring at 15–25 years. The sealed unit can be replaced independently of the frame at approximately £60–£120 per unit, significantly cheaper than full window replacement. Hardware (handles, hinges, locks) should be lubricated annually with a silicone-based lubricant — hardware replacement costs £30–£80 per window if worn. uPVC does not require painting but can be cleaned with a uPVC-specific cleaner (avoid bleach and solvent-based cleaners that cause yellowing). Foil-wrapped coloured uPVC: the foil wrap can peel or lift over time, particularly on south-facing elevations — specify a 10-year guarantee on the foil wrap from the manufacturer.
