Window Replacement Cost UK | uPVC vs Aluminium vs Sash (2026)  

Window replacement cost in the UK typically runs from £300 to £1,200 per window installed. That depends heavily on frame material and style. A full house replacement ranges from around £3,500 for a small flat up to £14,000 for a larger four-bedroom property. This guide breaks down exactly where your project sits within that range, for homes across Buckinghamshire and Oxfordshire.

If you have had one quote back and want to know if it is fair, you are asking the right question. Most homeowners get a single number and no way to check it against anything else. This guide gives you that check, with real UK pricing by material, style, and house size.

Prices in this guide reflect the current UK market for 2026. They cover uPVC, aluminium, and timber frames, every common window style, and full house projects from a small flat up to a larger family home. Where a figure depends on your specific property, we say so, rather than pretending one number fits every home in Buckinghamshire and Oxfordshire.

Average Cost of Window Replacement in 2026

New windows cost between £300 and £1,200 per window, with your final figure shaped by material, style, and glazing choice. A full house project moves that into thousands, not hundreds.

Average Window Replacement Cost Per Window

A single window typically costs £300 to £1,200 fitted. A basic white uPVC casement sits at the bottom of that range. A bay window in a premium material sits at the top.

Average Cost of Window Replacement for a Full House

A full house project generally costs £3,500 to £14,000, depending on the number of windows and the property size. Window count matters more than floor area here.

Quick-Reference Price Table (Low, Median, High)

Project	Low	Median	High
Single uPVC casement	£350	£475	£600
Single uPVC sash	£700	£900	£1,100
Single aluminium casement	£700	£1,050	£1,400
Full house, small flat	£2,000	£3,250	£4,500
Full house, 4 bed	£7,000	£10,500	£14,000

New Windows Cost by Frame Material

uPVC Window Replacement Cost

uPVC casement windows cost £350 to £600 fitted, the most affordable frame material available. Low maintenance and thermal efficiency are the main reasons it remains the most popular choice in the UK. Our uPVC windows cost guide covers pricing by size and style in full detail.

White vs Grey vs Woodgrain uPVC Cost Differences

White uPVC is the base price. Grey, anthracite, and woodgrain foil finishes typically add a percentage on top, the same pattern seen across most uPVC window ranges.

Aluminium Window Replacement Cost

Aluminium casement windows cost £700 to £1,400 fitted, roughly double the uPVC price for a comparable size. Slim sightlines and long-term durability are what you are paying the premium for.

Why Aluminium Costs More Than uPVC

Aluminium needs a thermal break to perform well, which adds manufacturing cost. The frame itself is also stronger and more expensive to produce than uPVC.

Composite Replacement Window Prices

Composite windows generally price above standard uPVC, reflecting the hybrid construction of a low-maintenance exterior with better insulation performance. Ask your installer for a specific figure at survey stage, since composite pricing varies more by specification than the other materials here.

Composite tends to sit closest to timber on price, without the repainting timber demands. That makes it a reasonable middle ground for homeowners who want a premium look without ongoing maintenance, though it rarely competes with uPVC on straightforward budget terms.

Replacement Windows Prices by Window Style

Casement Replacement Windows Prices

Casement windows cost £350 to £600 fitted in uPVC, the cheapest and most common style in the UK. Full details on this style are on our casement windows page.

Sash New Windows Cost

Sash windows cost £700 to £1,100 fitted, roughly double a standard casement. The balance mechanism and box frame construction account for the difference. Our sash window cost guide covers this style in full, including repair versus replacement.

Tilt and Turn Window Cost

Tilt and turn windows carry a premium over standard casement, reflecting the dual opening mechanism and extra hardware involved. Our tilt and turn window guide covers exactly what drives that premium and whether it suits your property.

Bay Window Change Cost

Bay windows cost £1,200 to £3,500, the most expensive standard style. Multiple panels and structural support work both add to the total. Full details are on our bay windows page.

Why Bay Windows Cost More Than Standard Windows

A bay window is built from several panels rather than one, each priced separately, then joined with structural support most single windows never need.

Bow New Windows Cost

Bow windows follow a similar cost pattern to bay windows, generally at the higher end of that £1,200 to £3,500 range, since a curved frame usually means more bespoke manufacturing per panel.

Flush Sash and Heritage Window Cost

Flush sash windows typically cost 10 to 15 percent more than standard casement, reflecting the tighter manufacturing tolerances the flush profile demands. Full pricing is on our flush sash windows page.

Average Cost of Window Replacement by House Size

New Windows Cost for a 2-Bed House

A 2-bed house with 6 to 8 windows typically costs £3,500 to £6,000 for a full replacement, depending on style and material mix.

Window Change Cost for a 3-Bed House

A 3-bed house with 8 to 12 windows typically costs £4,500 to £9,000. This is the most common project size across Buckinghamshire and Oxfordshire.

uPVC vs Aluminium Cost for a 3-Bed Semi

A typical 3-bed semi in uPVC sits toward the lower half of that £4,500 to £9,000 range. The same project in aluminium sits well above it, given aluminium runs roughly double uPVC per window.

Average Cost of Window Replacement for a 4-Bed and 5-Bed House

A 4-bed house with 12 to 16 windows typically costs £7,000 to £14,000. Larger 5-bed properties, or those with bay windows included, sit toward the top of that bracket.

Glazing Costs: Double, Triple and Secondary Glazing

Double Glazing Cost

Double glazing is the standard UK specification behind every price above. Our double glazing cost guide covers this in full, including whole house pricing by property size.

Triple Glazing Cost

Triple glazing adds roughly 20 to 30 percent on top of double glazing pricing. It is worth it mainly on exposed or north-facing elevations, not as a blanket upgrade across every window.

Secondary Glazing Cost

Secondary glazing, a retrofit second pane fitted inside an existing frame, is the cheapest glazing upgrade available. It suits listed buildings well, where the original frame has to stay in place, though it performs less efficiently than a full double-glazed replacement.

Best Glazing Option for Listed and Period Properties

Secondary glazing is often the only realistic option where original frames must be preserved. Standard double or triple glazing usually is not available if consent requires the existing frame to remain.

What Affects Window Change Cost?

Window Size, Shape and Custom Dimensions

Larger windows need more frame and glass, which raises material cost directly. Non-standard shapes, common in older properties, add manufacturing time on top.

Frame Colour and Finish

White is the base price across every material here. Coloured or woodgrain finishes typically add a percentage on top, rather than a fixed amount.

Glazing Specification and Energy Rating

Higher energy ratings generally mean argon gas fill and Low-E coatings, both of which add cost over a basic double glazed unit.

Installation Complexity and Property Access

Upper floor windows needing scaffolding, or narrow terraced access limiting delivery vehicle size, both add labour cost beyond the window price itself. Vertical sliders, covered on our vertical sliders page, are one style where installation complexity adds more than usual, given the sash weight involved.

One thing that surprised me, working across this market for years, is how often homeowners budget carefully for the window itself and then get caught out by access. A narrow Victorian terrace with no side passage can turn a straightforward job into one needing hand-carried materials and a longer install day, purely down to how the property was built, not the window chosen.

Location and Regional Price Differences

Labour rates in the South East, including Buckinghamshire and Oxfordshire, generally sit above the wider UK average. This is a genuine regional factor, not a generic caveat.

Number of Windows and Bulk Discounts

Ordering multiple windows together generally lowers the cost per window, since delivery and labour are shared across the whole job rather than a single unit.

Hidden Costs That Affect Your Window Replacement Quote

Scaffolding Costs

Upper floor windows without safe ladder access may need scaffolding, a genuine additional cost often left off an early ballpark figure.

Sill and Cill Replacement Costs

A worn or damaged sill sometimes needs replacing alongside the window itself. Ask specifically whether this is included, since it is easy to miss on a quick quote.

Plastering and Decorating After Installation

Making good around the new frame is usually included in a fitted price, but full replastering or redecorating beyond that point is not. Confirm the boundary before work starts.

Waste Disposal and Removal Costs

Removal and disposal of your old windows should be included in any genuine supply and fit quote. If a quote looks unusually low, check this has not been left out.

Additional Costs for Listed Buildings and Conservation Areas

If your property is listed or in a conservation area, check with your local planning department before ordering. Heritage spec requirements, such as slim sightlines or specific frame colours, add real cost over a standard specification.

Window Installation Labour Costs

Hourly and Day Rate for Window Fitters

Straightforward window fitting typically works out to roughly 1 to 2 hours per window for a team of two, priced either per window or as a day rate depending on the installer.

How Long Does Window Installation Take?

A small project of a few windows is often a one-day job. A full house replacement usually takes 2 to 4 days, weather permitting.

Installation Time by House Size

A flat or 2-bed house typically takes a single day. A 3- or 4-bed house typically takes 2 to 4 days, depending on window count and access.

Should You Repair or Replace Your Windows?

Signs You Need Window Replacement, Not Repair

Condensation between the panes means the sealed unit has failed and cannot be repaired on its own. Frames that no longer open, close, or lock properly, or visible warping and cracking, are also signs that replacement is the sensible route rather than another repair.

When a Simple Window Repair Is Enough

A stiff hinge, a worn handle, or a failed seal around a single pane can often be repaired rather than replaced, provided the frame itself is structurally sound. Here is the part most first-time buyers get wrong. They assume any window problem means a full replacement, when a targeted repair is often the better value option.

How to Get an Accurate Window Replacement Cost Quote

What Should Be Included in Your Quote

A genuine quote should be itemised by window, state the glazing specification, include your installer’s FENSA number, and set out the warranty terms in writing.

Questions to Ask Before Hiring a Window Installer

Ask whether fitting is in-house or subcontracted, what the realistic lead time is from survey to installation, and whether removal and disposal of old windows is included in the price quoted.

Red Flags to Avoid When Comparing Quotes

A quote with no FENSA number, no written warranty, or a price that seems far below every other quote you have received is worth questioning before you sign anything.

How to Measure Windows for an Accurate Price

Step-by-Step Guide to Measuring Window Apertures

Measure the width and height of the opening at three points each: top, middle, and bottom. Use the smallest measurement for each dimension, since older openings are rarely perfectly square. This gives you a rough figure to sanity-check a quote against, though a professional survey is still the only way to get an exact, made-to-measure price.

Building Regulations and Planning Permission for New Windows

When You Need Planning Permission

Standard like-for-like window replacement generally falls under permitted development and does not need separate planning permission.

FENSA and Building Compliance Certificates

A FENSA-registered installer can self-certify compliance with Building Regulations Part L, avoiding a separate building control inspection. You can check what the scheme covers via FENSA, the official UK competent person scheme for window and door installation.

A Real Buckinghamshire Example

Based on Flush Sash UPVC’s experience fitting windows across Buckinghamshire and the Home Counties, a homeowner near High Wycombe replacing 8 windows on a 3-bed semi would typically sit within the £4,500 to £9,000 bracket, with uPVC casement bringing the project toward the lower end. 

A comparable project near Oxford city centre, on a period terrace with one bay window and conservation area status, would typically land toward the top of that bracket or above it, once heritage spec requirements and the bay premium are factored in.

That gap between two similar-sized projects is exactly why a proper survey matters more than any guide price. The window count might be identical. The property type, access, and planning status rarely are.

A third comparison worth mentioning: a new build estate near Milton Keynes generally sits at the most predictable end of any pricing range. Standard sizes, easy access, and no heritage consideration mean quotes here tend to cluster tightly together, which is not something you can assume for an older property just a few miles away.

Window Replacement Cost in Plain Terms

Window replacement costs in the UK come down to a small set of honest variables. Material, style, size, and glazing spec drive almost everything else. A standard uPVC casement sits at £350 to £600 per window. A full house project typically falls between £3,500 and £14,000, depending on property size.

The most useful thing you can do with this guide is treat it as a checklist against your own quotes, not a replacement for one. Match your material, style, and window count against the figures here. If a quote sits well outside these ranges, ask why, rather than assuming higher always means better or lower always means worse.