Replacing windows in a UK home typically costs £350 to £2,800 per window in 2026 depending on material, style and size. A full set of windows for a standard 3-bedroom semi costs £4,000 to £12,000. uPVC casement windows are the most affordable option starting from £350, while timber sash windows can reach £2,800 each. Prices include supply, installation and disposal of old frames — always get at least three quotes from FENSA-registered installers.
Window Replacement Cost Calculator
Select your window type, material and quantity for a personalised estimate based on 2026 UK prices including installation.
Window Replacement Costs by Material and Style (2026)
The table below shows typical per-window costs including supply, installation, and removal of old frames. Prices assume standard-sized windows (roughly 1.2m × 1.0m for casement, 1.8m × 1.0m for sash). Larger or non-standard sizes will cost more.
| Window Type | uPVC | Timber (softwood) | Aluminium |
|---|---|---|---|
| Casement | £350 – £800 | £800 – £1,500 | £900 – £1,600 |
| Sash | £600 – £1,200 | £1,200 – £2,800 | £1,400 – £2,500 |
| Bay / Bow | £1,200 – £2,500 | £2,000 – £4,000 | £2,500 – £5,000 |
| Fixed Pane | £250 – £500 | £500 – £900 | £550 – £1,000 |
Full house estimates: A typical 3-bed semi with 8–10 windows costs £4,000–£9,500 in uPVC, £8,000–£15,000 in timber, or £9,000–£18,000 in aluminium. These are supply-and-fit prices — supply-only is typically 40–50% less.
What Affects Window Replacement Cost
Several factors can move your window replacement cost significantly from the averages above.
Frame material. uPVC remains the most popular and affordable choice in the UK, offering good thermal performance with minimal maintenance. Timber is more expensive but preferred for period properties and conservation areas where planning rules may require it. Aluminium offers the slimmest sightlines and longest lifespan (40+ years) but comes at a premium.
Window style. Casement windows are the simplest and cheapest to manufacture and install. Sash windows cost significantly more due to their counterbalance mechanism and larger frame sizes. Bay and bow windows are the most expensive because they involve structural elements (support poles or cantilevered platforms) and multiple panes.
Glass specification. Standard double glazing is included in most quotes. Upgrading to triple glazing adds £50–£150 per window but improves energy ratings from B/C to A+. Acoustic glass, self-cleaning coatings, and integral blinds all add to the per-unit cost.
Access and removal. Ground-floor windows on accessible elevations are straightforward. Upper-floor windows may need scaffolding (typically £400–£800 for a scaffold tower or single-lift setup). Removing old metal or timber frames that are cemented in takes longer than removing modern uPVC click-fit frames.
Planning and building regulations. All replacement windows must comply with Part L (thermal performance) of the Building Regulations. Most FENSA-registered installers self-certify compliance, avoiding the need for a separate building control application. In conservation areas or listed buildings, you may need planning permission and must use approved materials — usually timber at higher cost.
Region. London and the South East typically run 15–20% above national averages for both supply and installation labour. The North of England, Scotland and Wales tend to be 10–15% below.
How to Save on Window Replacement
New windows are a significant investment but there are practical ways to manage costs without compromising quality or energy performance.
Replace all windows at once. Most installers offer a discount of 5–15% when you replace all windows in one visit rather than doing them room by room. You also avoid repeat scaffolding costs and the hassle of multiple installation days.
Choose standard sizes where possible. Non-standard or bespoke window sizes cost more because frames must be custom-manufactured. Where building regulations and aesthetics allow, choosing stock sizes can reduce per-unit costs noticeably.
Compare supply-and-fit vs supply-only. If you have a trusted builder or are competent with installation, buying windows supply-only and fitting them separately can save 30–40%. However, you will need to arrange your own FENSA certification or building control sign-off, which adds £250–£400.
Get multiple quotes. Window prices vary widely between installers. Large national firms typically charge more than local independents for the same product. Always get at least three quotes and check that each includes the same glass specification, hardware, and guarantee period.
Check for grants. Some local authorities and energy schemes offer grants towards energy-efficient window upgrades, particularly for low-income households. The Energy Bills Support Checker can help you find available schemes.
The Window Replacement Process
Understanding what happens during a window replacement helps you plan around the disruption and ensures you know what to expect from your installer.
Survey and measurement. A surveyor visits to take precise measurements of each opening, check the condition of the surrounding brickwork and lintel, and discuss your requirements (style, colour, glass spec, handle type). This visit usually takes 30 to 60 minutes for a full house and is free with most installers. Allow four to eight weeks between survey and installation for manufacturing.
Installation day. Each standard casement window takes roughly one to two hours to replace. The fitter removes the old frame, checks the structural opening, fits the new frame with mechanical fixings and expanding foam, trims the internal plasterwork if needed, and seals the outside with silicone. A full house of eight to ten casement windows is typically completed in two days. Sash or bay windows take longer — a full set may need three to four days.
After installation. The installer should leave the area clean, remove all old frames and packaging, and provide you with a FENSA certificate (or equivalent competent-person certificate) confirming compliance with Building Regulations Part L. Keep this certificate — it is required when selling the property. Most guarantees cover the glass unit (sealed unit) for ten years, the frame for ten to twenty years, and the hardware (hinges, handles, locks) for five years.
Questions to Ask When Getting Window Quotes
Window replacement quotes can vary enormously for the same property. Asking the right questions ensures you compare like with like and avoid unexpected charges.
What glass specification is included? Ask whether the quote covers standard double glazing (typically B-rated) or a higher specification. Upgrading to A-rated or triple-glazed units improves thermal performance and may qualify for energy grants, but adds to the price. Confirm the U-value of the glass unit being offered.
Is scaffolding included? Some installers include scaffolding in the headline price while others quote it as an extra. For upper-floor windows, scaffold hire typically adds £400 to £800, so this can make a significant difference when comparing quotes.
What about making good? Removing old frames sometimes damages the internal plaster reveal around the window. Some installers make good with plaster or capping trim as standard; others leave it for you to arrange. Ask what the quote includes and budget accordingly if it does not cover internal finishing.
Is the FENSA certificate included? FENSA-registered installers self-certify compliance with Building Regulations and register the work automatically. If the installer is not FENSA-registered, you will need a separate Building Control application (£250 to £400), which eats into any apparent saving from a cheaper quote.
What guarantee applies? Ask for the guarantee in writing before signing. Check whether it is an insurance-backed guarantee (IBG), which protects you if the company ceases trading. Some installers provide frame, glass and hardware guarantees of different lengths — confirm all three.
Sources & References
- Checkatrade — New Windows Cost Guide 2026
- Federation of Master Builders — Window Prices 2026
- GOV.UK — Building Regulations Part L
Costs shown are typical ranges based on published trade data. Your actual cost depends on window sizes, property type and chosen installer. Always obtain multiple quotes from FENSA-registered firms. Last checked August 2026.