Double Glazed Windows Cost Guide
Double glazed window installation costs in the UK can start from around GBP 350 for a single basic window and rise to GBP 8,000 to GBP 15,000 for a full 3-bedroom house, depending on style, material, glazing choice, and access. This guide covers realistic 2026 price ranges, common window types, labour costs, likely extras, and what to check before hiring a window installer.
Get free quotes from local tradespeople
Enter your postcode to see who's available in your area
Quick Cost Summary
Prices are indicative and vary by location, property type, and specification. Always get at least three quotes.
Types of Double Glazed Window Project
uPVC Casement Windows
The most common and budget-friendly double glazing option for many homes. uPVC casement windows usually offer the best value for standard replacements.
Pros
- Usually the cheapest overall option
- Low maintenance
- Widely available across the UK
Cons
- Less premium in appearance than some alternatives
- Style choices can be more limited on some budgets
Best for: Most straightforward whole-house replacement projects
Sash or Period-Style Windows
These are often chosen for older or character properties where appearance matters. They usually cost more than basic casement windows.
Pros
- Better suited to period-style homes
- Can improve kerb appeal significantly
- Available in modern energy-efficient versions
Cons
- Higher product and installation cost
- Can involve more detailed fitting
Best for: Period homes and projects where style is as important as energy performance
Aluminium, Composite, or Premium Glazing
Higher-end window systems often cost more but can offer slimmer sightlines, stronger frames, and a more premium finish.
Pros
- Premium look and feel
- Strong frame performance
- Can suit contemporary properties well
Cons
- More expensive than standard uPVC
- Project costs rise quickly on whole-house jobs
Best for: Higher-spec renovation or new-look projects with more budget flexibility
The final quote depends on both the style of window and the scale of the project, from replacing one unit to fitting a whole house.
What Affects the Cost
- Number of windows being replaced
- Window style, size, and opening mechanism
- Frame material such as uPVC, timber, aluminium, or composite
- Access requirements and whether scaffolding is needed
- Any lintel, making-good, or trim work required
- Certification and compliance requirements such as FENSA or Certass
Labour Cost Breakdown
Labour is typically 30–50% of the total installation cost. The complexity of the job determines how long it takes.
What Is Usually Included
- Removal of old frames and glazed units
- Supply and fitting of the new windows
- Sealing, trimming, and basic making good around frames
- Glass and frame installation labour
- Compliance paperwork or certification where applicable
Extra Costs to Expect
These aren't always required, but it's worth knowing about them before you get quotes.
Running Costs & Potential Savings
Good quality double glazing can help reduce draughts and support lower heating use, especially if you are replacing very old or failing windows. The exact benefit depends on the rest of the property insulation and the standard of the new units being fitted.
Ready to get quotes?
Compare free, no-obligation quotes from trusted local tradespeople. No sign-up needed.
Get Free QuotesWhat to Check Before Hiring
Use this checklist when getting quotes to make sure you're hiring the right person at the right price.
- Confirm whether the quote includes installation and certification
- Check exactly which frame material and glazing spec are included
- Ask whether trims, sealing, and making good are included
- Check if scaffolding or difficult access has been priced in
- Ask about frame, glass, and workmanship guarantees
- Confirm the installer can provide the right compliance paperwork
Frequently Asked Questions
How much does double glazing cost in the UK?
Single windows can start from a few hundred pounds, while full-house projects often run into several thousand depending on style, material, and installation complexity.
How much does it cost to replace windows in a 3-bed house?
A typical 3-bedroom house often falls roughly in the GBP 8,000 to GBP 15,000 range, although premium materials or complex access can push costs higher.
Are sash windows more expensive than casement windows?
Usually yes. Sash windows tend to cost more because the products and fitting are often more specialised.
What certification should I look for?
Installers commonly provide FENSA or Certass certification to show the installation meets the relevant building regulations requirements.
Does triple glazing cost more than double glazing?
Yes. Triple glazing usually costs more and is generally chosen where extra insulation or noise reduction is a higher priority.
What affects the quote the most?
Window style, material, quantity, access, and any associated structural or finishing work are usually the main factors behind price differences.
Get free quotes from local tradespeople
Enter your postcode — we'll match you with available tradespeople in your area