Average uPVC window replacement prices in the UK
In the UK, replacement uPVC windows typically cost between £450 and £950 per window fully installed for standard casement frames. Sliding sash windows and curved bay windows command higher prices, typically £800 to £1,600 per window due to complex counterbalance mechanisms and multi-segment frame assembly.
Upgrading from standard double glazing to A-rated triple glazing generally adds 20% to 30% to the window unit cost, delivering superior thermal insulation (U-values as low as 0.8 W/m²K) and enhanced acoustic dampening.
FENSA certification and Building Regulations
Under UK Building Regulations (Part L), all replacement windows must achieve an energy rating of Band B or higher, or a U-value of 1.4 W/m²K or better. Installers registered with FENSA or CERTASS can self-certify their work, providing you with an official compliance certificate essential when selling your home.
Frames in non-standard colors (such as Anthracite Grey, Chartwell Green, or Golden Oak woodgrain effect) carry a 15% to 25% premium over standard brilliant white uPVC.
Worked example: 8 casement windows in an average 3-bed semi
Replacing 8 standard white casement windows with A-rated double glazing, including professional installation and disposal of old timber frames.
Supply cost for 8 quality uPVC casement units totals £3,600 (£450 each). Installation labour across two days totals £1,600 (£200 each). Old frame removal and disposal fees add £320 (£40 each), resulting in a total installed cost of approximately £5,520.
Inputs for the window price calculator
Number of windows
Total count of individual window units being replaced.
Window style
Casement, sliding sash, tilt and turn, or bay window.
Glazing specification
Standard A-rated double glazing or high-efficiency triple glazing.
Frame colour
Standard white uPVC or coloured/woodgrain finishes (e.g. Anthracite Grey).
Installation service
Fully installed by FENSA-certified fitters or supply-only DIY.
Removal and disposal
Include dismantling and recycling of existing wooden or aluminium frames.
CALCULATOR QUESTIONS
UK uPVC windows price calculator questions
How long do uPVC windows last?
Quality uPVC windows typically last 20 to 35 years before seals degrade or frames discolour, requiring minimal maintenance beyond periodic hinge lubrication.
Is triple glazing worth the extra cost in the UK?
Triple glazing is especially worthwhile for north-facing rooms, noisy roadside properties, or highly insulated homes aiming for Passivhaus standards, but standard A-rated double glazing offers the best cost-to-savings balance for most UK homes.
What is a FENSA certificate and do I need one?
A FENSA certificate proves that replacement windows comply with UK Building Regulations. You will need this certificate when selling your property; without it, you may have to purchase indemnity insurance.
How much money do new double glazed windows save on heating bills?
According to the Energy Saving Trust, replacing single glazing with A-rated double glazing in a detached house saves approximately £180 to £230 per year on energy bills.
Are coloured uPVC windows more expensive than white?
Yes. Coloured foils (such as Anthracite Grey or woodgrain finishes) typically add 15% to 25% to the window supply price compared to standard white uPVC.