Your Estimated Cost
Cost Breakdown
What Does This Include?
✓ Full supply of windows with your chosen specifications
✓ Professional installation by certified fitters
✓ Removal and disposal of old windows
✓ All necessary sealing and finishing work
✓ Manufacturer’s warranty (typically 10-15 years)
How to Use This Calculator
Getting an accurate estimate for your window replacement project is straightforward. Start by selecting your preferred window material – uPVC remains the most budget-friendly option, whilst timber offers a classic aesthetic at a premium price point.
Next, choose your window style. Casement windows are the most economical choice, whilst bay and bow windows cost more due to their complex installation requirements. Select the size that matches your existing windows, or measure your window openings if you’re unsure.
The calculator automatically includes installation labour costs, which typically range from £150-£350 per window depending on complexity. For ground-floor, easily accessible windows, you’ll pay less than for upper-floor installations requiring scaffolding.
What Affects Your Window Costs?
Material Choice
uPVC windows dominate the UK market for good reason – they’re affordable, low-maintenance, and energy-efficient. Expect to pay £160-£1,240 per window installed. Aluminium windows cost 20-30% more but offer slimmer frames and better strength. Timber windows are the premium option at £240-£1,860 per window, requiring regular maintenance but providing excellent insulation and traditional charm.
Window Size Matters
A small 600mm x 900mm window might cost £400-£600 installed, whilst a large 1400mm x 1400mm window could set you back £800-£1,500. Bay and bow windows command higher prices due to their multi-panel design and complex installation – expect £1,500-£4,000 for a typical three-panel bay window.
Glazing Technology
Double glazing is standard across the UK, but triple glazing costs about 15-25% more upfront. However, A++ rated triple glazing can save you an extra £40 annually compared to A-rated double glazing. If you live in a colder region or near a noisy road, triple glazing might be worth the investment.
Installation Complexity
Ground-floor installations are cheapest. Upper-floor windows needing scaffolding add £500-£1,500 to your project cost. Listed buildings requiring special permissions or non-standard window sizes also increase expenses significantly.
Material Comparison
| Material | Cost Range | Lifespan | Maintenance | Best For |
|---|---|---|---|---|
| uPVC | £160-£1,240 | 20-25 years | Very Low | Budget-conscious homeowners |
| Aluminium | £210-£1,615 | 30-40 years | Low | Modern aesthetics, slim frames |
| Timber | £240-£1,860 | 30+ years | High | Period properties, conservation areas |
| Composite | £900-£1,900 | 35+ years | Low | Best of both worlds |
Money-Saving Tips
Time Your Purchase
Window companies often offer better rates during quieter months (January-March). You might save 10-15% by avoiding peak summer season when demand soars.
Get Multiple Quotes
Always obtain at least three quotes. Prices can vary by 30% or more between suppliers for identical specifications. Don’t automatically choose the cheapest – check reviews and warranties too.
Replace Multiple Windows
Replacing all your windows at once reduces the per-window labour cost. Installers often offer discounts for whole-house projects, potentially saving £200-£500.
Consider Grants
Check eligibility for government energy efficiency grants. The Energy Company Obligation (ECO4) scheme helps qualifying homeowners reduce installation costs significantly.
Frequently Asked Questions
When to Replace Your Windows
Knowing the right time to replace windows saves you money in the long run. Here are clear signs your windows need replacement:
• Visible rot or damage to frames that affects structural integrity
• Condensation between double-glazed panes indicating seal failure
• Windows that won’t open, close, or lock properly (security risk)
• Significant draughts even when windows are closed
• Your energy bills have increased noticeably
Single-glazed windows in UK homes should definitely be replaced. They lose heat 3-4 times faster than modern double glazing, costing you hundreds of pounds annually in wasted energy. Even double-glazed windows over 20 years old are far less efficient than current standards.
What to Expect During Installation
Professional window installers follow a systematic process to minimise disruption to your home. The team typically arrives early morning and begins by protecting your floors and furniture with dust sheets.
They’ll remove old windows carefully, disposing of them responsibly (good companies include this in their quote). The new frames are fitted, sealed thoroughly with expanding foam and silicone, and checked for level and operation. External trims and internal finishes are then added.
Expect some dust and noise during installation, though professionals minimise both. Each window takes 30-60 minutes, meaning a typical house is completed in 1-2 days. You’ll receive Building Regulations certificates within 4-6 weeks – keep these safe for future property sales.
Avoiding Common Mistakes
Don’t Rush Your Decision
High-pressure sales tactics are common in the window industry. Never sign contracts on the spot, regardless of “today only” discounts offered. Take time to compare quotes properly and research companies thoroughly.
Specify Energy Ratings
Always ask for specific Window Energy Ratings (WER), not just vague claims of “energy efficient.” A-rated or higher should be standard, but some companies still push lower-rated products at premium prices.
Check What’s Included
Some quotes exclude VAT, old window removal, or external trims. Get everything in writing: materials, specifications, installation scope, disposal, guarantees, and total price including VAT. Hidden costs often appear later otherwise.
Verify Credentials
Installers should be FENSA, CERTASS, or equivalent registered for Building Regulations self-certification. This isn’t optional – it’s a legal requirement. Ask to see registration certificates before hiring anyone.