COST GUIDES
How much do flush casement windows cost in 2026?
Updated 07/26
Fast Facts
Small window (600 x 900 mm), average supply and fit: £350
Standard window (1,200 x 1,200 mm), average supply and fit: £500
Full house (3-bed, 12 windows), average supply and fit: £7,500
Typical premium: Flush casement windows usually cost around 10–15% more than standard casement windows
Whether you're replacing tired old windows or updating the look of your home, flush casement windows offer a traditional appearance with modern performance.
Their clean, flat finish makes them a popular choice for everything from period cottages to contemporary new-builds.
They cost a little more than standard casement windows, but many homeowners feel the improved appearance is worth the extra investment.
This guide explains typical uPVC flush casement window prices, what affects the cost and how to compare quotes from checked window fitters working in your area.
How much do flush casement windows cost?
Prices vary depending on the size of the window and the specification you choose, but the figures below provide a useful starting point when budgeting for your project.
| Cost provided item | Unit | Range - Low +VAT | Range - High +VAT | Average cost +VAT |
|---|---|---|---|---|
| Flush casement window | (supply and install) 600 x 900 mm | £300 | £400 | £350 |
| Flush casement window | (supply and install) 1,200 x 1,200 | £450 | £550 | £500 |
| Flush casement window | (supply and install) 940 x 1600 mm | £470 | £570 | £520 |
| Full house uPVC casement | 3 bedroom, 12 windows | £5,000 | £10,000 | £7,500 |
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | ||||
As a guide, expect to pay around £350 for a small flush casement window, £500 for a standard-sized window and approximately £7,500 to replace all 12 windows in a typical three-bedroom home.
Flush casement windows generally cost 10–15% more than standard casement windows because of the more precise manufacturing needed to achieve their distinctive flush finish.
Get a quote for flush casement windows in your area
The best way to understand what your installation is likely to cost is to compare a selection of quotes from checked window fitters working in your area.
Find checked window fitters near you
What affects uPVC flush casement window prices?
The final cost isn't just determined by the size of the window. Small changes to the specification can quickly affect the overall price, particularly if you're replacing several windows at once.
Here's what to bear in mind when getting quotes:
Number of windows: More windows generally means a lower per-window cost, but the total will be higher
Window size: Larger windows cost more for both the frame and the glass
Glazing type: Double glazing is standard. Triple glazing costs more but improves thermal performance
Frame colour: Standard white uPVC costs less. Coloured or woodgrain finishes carry a premium
Installer location: Prices are higher in London and other cities than in rural areas
If you're comparing different window materials or styles, our timber windows cost guide, double glazing cost guide and new windows cost guide provide a broader overview of your options.
Because window installation affects weatherproofing, insulation and security, it's usually best carried out by an experienced window fitter.
On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.
Flush casement windows vs standard casement windows
At first glance, the two styles look similar, but there's one key difference:
A standard casement window closes against the frame
A flush casement window sits level with it, creating a flatter, more traditional appearance
Flush casement windows cost more than standard casement windows. You're typically looking at a 10–15% price premium, depending on the supplier and specification.
That's because the manufacturing tolerances are tighter: the sash has to fit precisely within the frame to achieve that flush finish.
Both types are available in uPVC, aluminium, and timber. For most homeowners choosing uPVC, flush casement windows are the better-looking option if budget allows.
For more information on all uPVC window types, visit the uPVC windows hub.
Flush casement windows pros and cons
If you're deciding whether flush casement windows are right for your home, weighing up the benefits alongside the additional cost can help you make the right choice.
Pros:
Clean, flat exterior finish: suits both period and modern properties
When fitted correctly, the flush design helps create a neat weatherproof seal while maintaining a clean, flat appearance
Increasingly popular with new-build developers and planners in conservation areas
Available in a wide range of colours and finishes
Cons:
Cost more than standard casement windows (roughly 10–15% more)
Require more precise installation: a poor fit ruins the aesthetic
Fewer off-the-shelf sizes available than standard casement windows
Flush casement windows cost calculator
The quickest way to estimate your budget is to think about the type of flush casement windows you'd like, their size and specification (frame material and glazing type).
Job Estimate Calculator
This calculator provides a guide price only. For an accurate figure for your installation, compare a selection of quotes from checked window fitters working in your area.
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uPVC flush casement windows cost checklist
Before choosing an installer:
Find a window fitter near you
Finding a checked window fitter through Checkatrade is straightforward.
When requesting quotes, it helps to include:
How many windows you want replacing
The size of each window (if known)
Whether you'd like double or triple glazing
Your preferred frame colour or finish
Whether any structural work around the window openings may be needed
Comparing a selection of quotes from checked window fitters working in your area is the easiest way to understand your options and what's included in each quotation.
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FAQs
Yes. Flush casement windows cost around 10-15% more than standard casement windows. The tighter manufacturing tolerances and more precise installation required push the price up. For most homeowners the premium is worth it for the cleaner look.
Most definitely. Flush casement windows sit flush within the frame to create a flat, smooth surface on the outside with zero overlaps. Sophisticated and stylish, with simple, clean lines, these windows fuse traditional style with contemporary design.
Casement windows typically cost between £300 and £570, depending on which size you choose. uPVC flush casement windows typically cost 30-40% less than timber equivalents and slightly less than aluminium versions. For sash window alternatives, see our guide to the cost of replacing sash windows.
No. Older flush casement windows didn't have an extra layer of sealing, so whenever it rained, damp could get in. Modern flush casement windows have an additional seal that prevents this, making them just as weatherproof as standard casement windows.
A standard casement window has a sash that overlaps the outer frame slightly when shut. A flush casement window sits level with the frame, giving a completely flat exterior. The flush design costs a little more but is considered the more attractive option, particularly for period homes and some new-builds.
A window fitter can typically replace a single casement window in 1-2 hours. For a full house (10-12 windows), allow one to two days. The exact time depends on the number of windows, ease of access, and whether any structural work is needed.
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