Window Replacement Cost Greater London: 2026 Prices

Replacing windows across a Greater London property runs from a few hundred pounds for a single uPVC unit to well over £15,000 for a full house of premium timber sash windows. Whereabouts you sit within that range depends on frame material, glazing type, property age and how easy your windows are to access.

Prices in the capital sit higher than the national average quoted by whatprice and similar comparison sites, largely down to labour rates and the number of period properties requiring bespoke or heritage-style replacement windows. A terraced house in Zone 2 with sash windows will cost considerably more to reglaze than a modern flat with standard casement units.

Any reputable window company London homeowners contact should give you a written, itemised quote after an on-site survey, not a phone estimate. This article sets out realistic 2026 fitted prices by style and material, then covers the borough-specific rules around conservation areas, planning permission and building control that catch out a lot of first-time buyers.

What Will New Windows Cost in Greater London?

Fitted window replacement costs in Greater London typically start around £450 for a small uPVC casement window and rise past £2,000 for large timber sash or bay windows. The final figure depends on the combination of frame material, glazing type, window style and how many units you're replacing at once.

Typical Fitted Prices by Window Style

Casement windows remain the cheapest option to install, with uPVC versions fitted from roughly £450 to £750 per window. Timber casements cost more, generally £900 to £1,600 fitted, reflecting the material and joinery involved.

Sash windows carry a premium because of their moving mechanisms and the skilled labour needed to fit them properly. Expect:

• uPVC sash windows: £700 to £1,300 fitted

• Timber sash windows: £1,200 to £3,500 fitted, depending on size and detailing

  
  

Bay windows and bow windows cost more again, since they involve multiple panes set at angles and often need structural support. A typical bay window replacement runs from £1,800 to £4,500 fitted, with larger or timber-framed bays reaching higher.

How Frame Materials and Glazing Change the Quote

Frame material shapes the bulk of your quote, alongside whether you choose double glazing or triple glazing. UPVC windows sit at the budget end, aluminium windows in the middle, and timber at the top.

Frame Material	Price Range (per window, fitted)	Notes
UPVC casement	£450-£750	Most common, low maintenance
Aluminium	£600-£1,400	Slim sightlines, durable
Timber	£900-£3,500	Best for period properties

UPVC casement windows and standard double glazing suit most modern flats and post-war terraces. Aluminium windows appeal where slim frames matter, often in extensions or contemporary refurbishments.

Triple glazing adds 15-25% to the glazing cost but improves the U-value significantly, which matters for reducing heat loss in older, draughtier London homes. A lower U-value means better insulation, so it's worth asking any window company London installer to quote both options side by side.

Whole-Home and Door Replacement Budgets

A full house of new windows in Greater London typically costs between £5,500 and £18,000, depending on property size and window count. A three-bedroom terrace with ten to twelve windows sits toward the middle of that range with uPVC, and toward the top with timber sash.

Door replacement often gets bundled into the same project. Patio doors cost from £1,200 to £3,500 fitted depending on size and frame material, while a standard front door replacement adds £600 to £1,800.

Remember that VAT at 20% applies to most window and door installation work, and reputable installers should always show this separately on your quote rather than folding it into a vague total.

London-Specific Costs, Rules and Choosing an Installer

Costs in Greater London run higher than the national average chiefly because of access difficulties, property density and the concentration of conservation areas across the capital. Terraced streets, restricted parking and older housing stock all push labour time up compared with a detached suburban home.

Why Access, Property Type and Location Affect Costs

Difficult access adds directly to your final bill. Upper-floor windows on a terraced house often need scaffolding, and scaffolding costs in London typically range from £500 to £1,500 depending on the size and duration of the job.

Flats above ground floor level, period conversions and properties on narrow streets all tend to attract higher quotes. Installers factor in the time needed to protect stairwells, carry materials through communal areas, or work around parking restrictions common in inner boroughs.

Property type matters as much as location. A Victorian terrace with original sash windows demands more careful removal and fitting than a 1990s new-build with standard casement openings.

When Planning Permission or Building Control Is Needed

Most window replacements in Greater London don't need planning permission, but conservation areas and listed buildings change that picture. If your property sits within a conservation area or under an Article 4 direction, you may need approval before altering window style, material or colour, even for like-for-like replacement.

Listed buildings almost always require planning permission for window changes, regardless of borough. Check with your local planning department before ordering anything if your home has listed status.

Building regulations apply separately from planning rules. All replacement windows must meet Building Regulations Part L for thermal performance, and work needs to be signed off through building control or a competent persons scheme.

This is where FENSA-registered installers make life considerably easier. A FENSA certificate confirms the work has been self-certified as compliant, which saves you contacting building control directly and matters when you come to sell the property.

What to Check Before Accepting a Quote

A proper on-site survey, a FENSA certificate, and clear itemisation of VAT and scaffolding costs are the three things worth confirming before you sign anything. Any window company London firm worth using will send a surveyor rather than quote from photos alone.

Ask these questions before accepting:

• Is the installer FENSA-registered, and will they provide a FENSA certificate on completion?

• Does the quote separate labour, materials, VAT and any scaffolding costs?

• What U-value do the proposed windows achieve, and does that meet Part L requirements?

• How will they seal and insulate the frames, and do they use expanding foam correctly around the reveals rather than relying on it as the sole seal?

  
  

Glazier London and similar established local firms typically provide all of this as standard, alongside a written guarantee covering both the frames and the installation labour. Getting three quotes from different installers, including at least one specialist in period properties if you have sash or bay windows, gives you a realistic sense of the market rate before committing.

For more guidance, explore “Residential Tempered Glass Suppliers London” and “Booking Residential Window Replacement London” for practical advice on glazing and replacement projects.

Conclusion

Window replacement costs across Greater London vary widely, from around £450 for a small uPVC casement window to £18,000 or more for a full house of timber sash windows. Frame material, glazing choice and window style drive most of that variation, while access, property type and conservation area status add London-specific costs on top.

Getting a proper on-site survey, checking FENSA registration, and confirming VAT and scaffolding costs upfront protects you from surprises once work begins. Comparing quotes from more than one window company London installer, and asking direct questions about U-values and building regulations compliance, puts you in a stronger position to judge whether a quote represents fair value for your property.