double glazing specialists in London
If you're looking for double glazing in London, you're in the right place. Pro-Fit Window Systems connects homeowners across Greater London with FENSA-registered double glazing installers who offer free, no-obligation quotes.
Whether you're replacing a single window or upgrading your entire home, we match you with up to 3 trusted local specialists — so you can compare prices and choose the best deal. The average homeowner in London saves £500–£1,500 by comparing quotes rather than accepting the first offer.
Double Glazing prices in London 2026
We've compiled current installed price ranges for double glazing in the Greater London area. Actual costs depend on window size and specification — compare quotes for a precise figure.
| Window Type | From (installed) | Up to (installed) |
|---|---|---|
| Casement (single) | £438 | £875 |
| Casement (large) | £625 | £1,125 |
| Sash Window | £750 | £1,375 |
| Bay Window (3-panel) | £1,500 | £4,000 |
| Tilt & Turn | £500 | £938 |
* Prices are estimates for London based on current market data. Your exact quote will depend on window size, specification and chosen installer.
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Get Quotes in London →FAQs — Double Glazing in London
What is the price of double glazing in London?
In London, you can expect to pay from £438 for a standard casement window installed, up to £4,000 for a full bay window. Prices in Greater London are slightly above the national average. The best way to get an accurate price is to compare quotes from local FENSA-registered installers using our free tool.
How many days will my double glazing installation take?
The time required depends on how many windows are being installed. In London, a single window can be replaced in 2–4 hours, while a whole-house installation typically takes 2–3 days. Your installer will confirm the schedule during their free property survey.
How do I know your London installers are trustworthy?
Absolutely. FENSA registration is a mandatory requirement for all companies in our London network. It certifies that installers meet UK Building Regulations standards and automatically includes a 10-year insurance-backed guarantee on every job.
Is planning permission required for window replacement in London?
Most standard window replacements in London are covered by permitted development rights and require no planning application. If your property is listed or sits within a conservation area in Greater London, additional consent from the local council may be needed — your installer can guide you through this.