Window of Opportunity: How Much Does It Really Cost to Replace Windows in the UK 2025?

Replacing windows is one of the most effective ways to improve the energy efficiency, security, and appearance of your home. But how much does it actually cost to replace windows in the UK? The answer depends on several factors including the type of window, the material, the size, the installer, and the region you live in.

In this guide, we will break down typical replacement window costs in the UK, explain what affects the price, and offer tips for getting the best value.

Average Cost to Replace Windows in the UK

On average, homeowners in the UK can expect to pay between:

- £300 to £700 for a standard uPVC casement window
- £500 to £1,000 for a sash window
- £1,000 to £2,500 for a large bay or bow window

These prices include supply and installation. Costs can vary depending on whether you are replacing a single window or upgrading the entire house.

Full House Window Replacement Cost (Typical UK Home)

For a typical 3-bedroom semi-detached home with 8 to 10 windows, full replacement costs generally range from:

- £3,000 to £5,000 for uPVC windows
- £5,000 to £8,000 for aluminium windows
- £7,000 to £10,000+ for timber or hardwood frames

Keep in mind that prices may increase if you choose triple glazing, shaped windows, or premium frame finishes.

Factors That Affect the Cost of Window Replacement

1. Window style: Casement windows are usually the most affordable. Sash, tilt-and-turn, and bay windows cost more due to their design and hardware.

2. Frame material: uPVC is the cheapest and most common. Aluminium offers a sleek look and long life but comes at a higher price. Timber is premium and ideal for period properties but requires more maintenance.

3. Glazing type: Double glazing is standard. Triple glazing adds 20 to 40 percent to the cost but improves thermal performance and noise reduction.

4. Size and shape: Larger or unusually shaped windows (arched, angled, etc.) require more materials and custom manufacturing.

5. Installation complexity: Upper-floor installations or windows that need lintel adjustments may involve extra labour.

6. Location: Installation costs are typically higher in London and the South East than in the North of England, Wales, or Scotland.

Cost Comparison by Window Type

uPVC Casement Window: £300 to £700
uPVC Sash Window: £500 to £1,000
Aluminium Casement Window: £600 to £1,000
Timber Casement Window: £800 to £1,500
Triple Glazed Window: Add 20% to 40% on top of double glazing costs

Should You Replace All Windows at Once?

Replacing all windows at the same time can be more cost-effective per unit due to savings on labour and scaffolding. It also ensures a consistent look throughout the property and avoids uneven wear between new and old frames.

However, if you are working with a tight budget, it is also acceptable to replace windows in phases, starting with the worst-performing or most exposed areas.

Tips to Save Money on Replacement Windows

- Get at least 3 quotes from FENSA-registered or Certass-certified installers

- Choose standard sizes and designs to avoid bespoke pricing

- Look for installers offering seasonal discounts or multi-window deals

- Ask about finance options if replacing all windows at once

- Check for local authority grants or energy efficiency schemes

How to Choose the Right Installer

Always choose a window installer who is registered with a recognised trade body such as:

- FENSA
- Certass
- TrustMark
- Checkatrade

These accreditations help ensure your windows are installed to current building regulations and may include warranty protection.

Do New Windows Add Value to Your Home?

Yes. New double or triple glazed windows can boost your home's energy efficiency, enhance kerb appeal, reduce noise pollution, and improve security. These benefits are attractive to buyers and can increase your property's resale value.

Conclusion

The cost to replace windows in the UK depends on a range of factors, but the investment can pay off in comfort, security, and energy savings. For most homeowners, uPVC windows offer the best balance of affordability and performance, while aluminium and timber provide premium aesthetics for a higher cost.

To get the best results, compare quotes, choose the right materials for your property, and work with a qualified installer. Whether you are replacing one window or a whole house, the right upgrade can make a big difference.