Instant double glazing cost estimate
Tailored to your property, material, glazing spec, style and postcode — plus energy savings, payback period and finance options. No email required.
Double glazing cost calculator
Based on 2026 UK market data. Tailored to your property, material, glazing spec and postcode — not a generic average.
| Windows (8) | £0 |
| Labour & installation | £0 |
| VAT (20%) | £0 |
| Total | £0 |
6 things that drive your price
Two identical-looking houses can get quotes £4,000 apart. Here’s what actually moves the number.
Spread the cost over time
Pick a term to see your monthly payment. 0% finance available on most installs over £3,000.
Material choice
uPVC is 40-50% cheaper than aluminium and 60% cheaper than composite. But premium materials last 10-15 years longer and suit heritage properties.
Window style
Casement is the UK standard. Sash (heritage) costs 45% more. Bay or bow windows cost 60% more due to structural glazing bars and angled fitting.
Glazing & energy rating
Triple glazing costs 20% more than double. A++ energy rating costs 8% more than A+. Both pay back through lower bills — especially in detached homes and the North.
Your postcode
London labour rates run 25% above the national average. Wales and Scotland are 10-12% below. Manchester, Leeds and Liverpool sit around 8% below.
Number of windows (bulk effect)
Fitting one window costs almost as much as fitting two — the labour and travel are the same. Most installers discount 8-15% for orders of 5+ windows.
Access & hidden costs
Upper-floor work needs scaffolding (£300-600). Lintel repairs add £150-400 per opening. Conservation areas may require planning consent (free pre-check).
🚩 Watch out for these hidden costs
- “VAT excluded” quotes — always ask for the VAT-inclusive total. Some installers advertise tempting ex-VAT numbers.
- Scaffolding charged extra — reputable installers include scaffolding for upper-floor work in the quote.
- “Disposal fees” — old-frame removal should be included, not added on the day.
- Lintel / making-good surcharges — a proper survey catches lintel issues upfront. If they’re flagged only mid-job, you’ve chosen the wrong installer.
- Decorator costs not mentioned — if internal reveals need plastering or repainting, good installers either include this or say so clearly.
- “Deposit of 50%” — anything over 25% is a red flag. Walk away.
Typical UK price benchmarks (2026)
Real FENSA-registered installer quotes for standard uPVC, A+ rated, casement style. Sash, triple glazing and bay style add premium.
| Property | Windows | London | SE England | Midlands | North / Scotland |
|---|---|---|---|---|---|
| Flat | 3-4 | £2,400 – £4,500 | £2,100 – £4,000 | £1,900 – £3,500 | £1,700 – £3,200 |
| Terrace | 6-8 | £4,800 – £9,000 | £4,200 – £8,000 | £3,800 – £7,000 | £3,400 – £6,400 |
| Semi | 8-10 | £6,000 – £11,300 | £5,200 – £10,000 | £4,750 – £8,750 | £4,250 – £8,000 |
| Detached | 10-14 | £9,000 – £17,000 | £7,900 – £15,000 | £7,125 – £13,125 | £6,375 – £12,000 |
| Victorian terrace (sash) | 8-12 | £11,500 – £19,000 | £10,000 – £17,000 | £9,000 – £15,000 | £8,000 – £13,500 |
Aluminium: add 40-50% · Triple glazing: add 20% · Bay/bow windows: add 60% · A++ rating: add 8%
How much will you actually save on bills?
Replacing single glazing with A+ double glazing saves the average UK semi-detached around £235/year on gas bills. A detached house saves closer to £305/year. Triple glazing lifts those figures by roughly 30% — about £305 and £395 respectively. (Energy Saving Trust, 2026 data, UK-wide average.)
The catch: energy savings depend heavily on what you’re replacing. If you’re moving from existing double glazing (installed 2000-2015) to modern A+ rated double glazing, annual savings drop to around £50-90 — still worth it for noise reduction and condensation, but not a short payback. Our calculator assumes you’re replacing single glazing or very old double glazing.
💡 Beyond energy savings: modern double glazing also cuts outside noise by 30-50% (Low-E glass with PVB interlayer), dramatically reduces condensation on the internal pane, adds roughly £2,000-£4,000 to a typical semi’s sale price (Rightmove HomeReport data, 2025), and qualifies A++ rated windows for 0% VAT under current UK energy-efficiency rules.
Can’t pay the full amount upfront?
Most Findfitter installers offer FCA-regulated finance with competitive rates. Typical options:
Best for smaller jobs where you can clear the balance in a year or two. Available on most £2,000+ jobs.
Typical for whole-house projects. A £7,500 job works out around £158/month over 60 months.
Useful if you’re between jobs or waiting on a bonus. Settle in full before the deferred period ends and there’s no interest.
All finance is subject to credit check and provided by FCA-regulated lenders. Installers will quote exact terms after your home survey.
Cost-calculator FAQs
How accurate is this estimate?
Our calculator uses 2026 mid-market prices from FENSA-registered UK installers. In practice, real quotes come within ±15% of the mid-range figure for a standard casement-style job. Sash, bay, conservation or bespoke work can vary more. Use the estimate as your benchmark — a quote 25% above our range is a red flag worth investigating.
Why does a national chain quote more?
National chains carry large marketing and sales-force overheads. Their door-to-door and TV advertising is baked into every quote — typically adding 30-40% to the final price. A local FENSA-registered installer with the same spec, same guarantees and same Building Regs compliance will usually be £2,000-£4,000 cheaper on a full-house job.
What’s actually included in an installer’s quote?
A complete quote should include: measuring and supply of all windows, removal of old frames, installation, initial making-good (plaster + render), waste disposal, FENSA/Certass Building Regs notification, 10-year insurance-backed guarantee, VAT. Ask every installer to itemise these lines so you can compare fairly.
When should I pay 0% VAT on new windows?
Since 2022, qualifying energy-saving materials (including A-rated windows) attract 0% VAT when installed in a residential property until 2027. The installer will either zero-rate the VAT on your quote directly or apply a reduced-rate exemption. This can save you roughly 16% on the total — always check VAT treatment before signing.
How long does installation take?
A standard 6-8 window terrace: 1-2 days. A 10-window semi: 2-3 days. A 14-window detached: 3-5 days. Full-house installs with scaffolding sometimes extend to a week. Good installers won’t start removing frames until all new units are on site and inspected.
Do I need planning permission for new windows?
Like-for-like replacements almost never need planning permission under permitted development. Exceptions: listed buildings, conservation areas, or properties covered by an Article 4 direction (common in parts of Didsbury, Headingley, Edgbaston, the Jewellery Quarter). A free pre-application check with your council takes 2-3 weeks and costs nothing — your FENSA installer can arrange it.
Can I claim a grant for new double glazing?
The ECO4 scheme (England, Wales, Scotland) funds or heavily subsidises energy-efficiency upgrades for low-income households and those on specific benefits. Home Energy Scotland offers interest-free loans up to £15,000 for Scottish homeowners. Check eligibility at gov.uk/energy-company-obligation or your installer can advise directly.
Does replacing windows add value to my home?
Rightmove’s 2025 HomeReport data shows new A-rated double glazing adds roughly £2,000-£4,000 to a typical UK semi’s sale price. It also significantly shortens average listing times in Energy Performance Certificate (EPC) D and E rated properties. The gains are higher in Victorian and older housing stock where existing windows are often single-glazed timber.
Sources & data used in this calculator
The calculator uses 2026 UK market data from the following authoritative sources:
- Energy Saving Trust — windows advice — annual energy-saving figures by property type (flat / terrace / semi / detached)
- British Fenestration Rating Council (BFRC) — window energy-rating methodology (A++ through E) and u-value testing
- FENSA — UK installer pricing benchmarks across 2024-2025
- Office for National Statistics — construction price indices — UK materials and labour cost trends
- GOV.UK — ECO4 scheme — eligibility framework referenced in grant-related calculator output
- UK Government — greenhouse gas conversion factors 2026 — grid carbon intensity used for CO² reduction estimate
- Rightmove 2025 HomeReport — property-value uplift figures referenced in the “Beyond energy savings” section
- Bank of England base rate data — informing 9.9% APR finance example (representative of FCA-regulated lender rates at date of publication)
Calculator estimates typically come within ±15% of real FENSA-registered installer quotes. Reviewed annually each January.
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