Casement windows
Often the lowest-cost starting point for UK homes. Costs rise with larger sizes, premium frames, trickle vents, colours and upgraded glazing.
Window replacement cost calculator
Window Replacement Cost Calculator UK
Estimate the cost of replacing windows in a UK home based on window type, number of windows, frame material, glazing, access, installation type and region. Use this calculator when replacing complete window units, including frames, glass and fitting.
Window replacement or double glazing upgrade?
The key difference is scope. Window replacement usually means removing and fitting a complete window unit, including frame, glass and installation. A glazing upgrade focuses on the glass performance, which may be suitable when the frames are still in good condition.
| Situation | Better starting point | Reason |
|---|---|---|
| Old or warped frames | Window replacement | The frame condition affects fit, insulation and long-term performance. |
| Failed seals or misted glass | Double glazing | The glass unit may be the main issue if frames are still sound. |
| Single glazing throughout the home | Window replacement | Replacing full units can improve frame performance and glazing together. |
| Good frames, poor insulation | Double glazing | A glazing-focused estimate may be more relevant. |
| Large opening or garden access | Patio doors | Door openings have different frame, threshold and fitting requirements. |
| Wide opening with folding panels | Bifold doors | Bifold systems are priced differently from standard windows. |
How window type changes replacement cost
Window style changes cost because the frame design, opening mechanism, size, manufacturing process and fitting time all vary. A simple casement window is usually easier to price than a sash, bay or specialist opening style.
Sash windows
Sash windows usually cost more because of the frame style, sliding mechanism, heritage look and fitting requirements.
Bay and bow windows
Bay and bow windows can cost more because they use multiple panels, angles, support details and more fitting time.
Typical UK window replacement cost ranges
These ranges are broad planning figures. Use the calculator above for a more specific estimate based on your window count, type, material, glazing, access and region.
| Project type | Typical range | Best next calculator |
|---|---|---|
| Single standard uPVC window | £450–£900+ | Window Replacement |
| Small project, 2–4 windows | £1,200–£4,500+ | Window Replacement |
| Typical house, 6–10 windows | £4,000–£12,000+ | Window Replacement |
| Full house, 10+ windows | £7,000–£20,000+ | Window Replacement |
| Glazing performance upgrade | Varies by glass and frame condition | Double Glazing |
What affects window replacement cost?
The number of windows sets the base estimate, but the final price is shaped by size, frame material, glazing, access, floor height, installation type and finish level.
Number of windows
More windows increase material and fitting cost, although larger projects may have a lower setup cost per window than a single-unit job.
Window style
Casement, sash, bay and tilt-and-turn windows sit in different cost bands because the frame design and fitting time differ.
Frame material
uPVC is usually the lower-cost option. Aluminium, timber and composite frames often increase the estimate.
Glazing specification
Triple, acoustic or performance glazing can increase cost because the glass units are heavier, more expensive and may need stronger frames.
Access and floor height
Upper floors, flats, restricted access, awkward parking or difficult lifting conditions can increase labour and setup time.
Installation complexity
Replacing like-for-like windows is usually cheaper than creating new openings, altering brickwork or dealing with damaged surrounds.
Replacing doors at the same time?
If your project includes entrance doors or garden access, compare this window estimate with the Front Door Cost Calculator, Patio Doors Cost Calculator and Bifold Doors Cost Calculator. Door systems use different frames, thresholds, locks, panels and installation details.
How this window replacement estimate is calculated
The calculator starts with a base cost per window for the selected window type, then adjusts the range using window size, frame material, glazing type, property type, access difficulty, installation type, specification level, region and contingency.
This approach is designed for early planning, not fixed quoting. The final price can change after measuring the openings, checking frame condition, reviewing access and confirming the exact product specification.
For more detail, read our methodology, pricing data and how costs are calculated.
Window and door decision paths
Use these paths to move from a rough project idea to the calculator that gives the most useful estimate.
I’m replacing old windows
Start with this Window Replacement Cost Calculator. It is the best fit when frames, glass and fitting are all part of the project.
I only want better glass performance
Use the Double Glazing Cost Calculator if the main focus is replacing or upgrading glass rather than full window units.
I’m replacing the entrance door
Use the Front Door Cost Calculator for composite, uPVC, timber or aluminium entrance door estimates.
I’m opening up the back of the house
Compare patio doors cost with the bifold doors cost calculator before choosing the door system.
Window replacement cost FAQs
How much does window replacement cost in the UK?
A single standard replacement window can cost hundreds of pounds, while a full-house replacement can run into several thousand pounds. The final range depends on window type, material, glazing, size, access and labour.
What is the cheapest window frame material?
uPVC is usually the lower-cost frame option for standard UK window replacement. Aluminium, timber and composite frames usually sit higher.
Are sash windows more expensive to replace?
Yes, sash windows often cost more than standard casement windows because of the frame style, sliding mechanism, finish and fitting requirements.
Is this the same as double glazing cost?
No. This page estimates full window replacement. For glazing-focused costs, use the Double Glazing Cost Calculator.
Does access affect window replacement cost?
Yes. Upper floors, flats, tight access, restricted parking and difficult lifting conditions can increase labour and setup costs.
Is triple glazing worth it?
Triple glazing can improve performance in some homes, but the value depends on property type, existing insulation, window orientation, noise needs and budget.
Can I use this calculator for flats?
Yes. Choose the 3+ storey or flat option if access is more difficult. Flats may need extra checks around permissions, access and building management rules.
Are CostIntel estimates fixed quotes?
No. They are planning estimates based on typical UK replacement window cost drivers. An installer needs to measure the openings and inspect the property before giving a fixed price.