Replacing windows in a standard UK semi-detached home now averages £12,000, according to Energy Saving Trust data. But that number is a baseline; your actual quote will swing by thousands depending on whether you choose uPVC, aluminium, or timber.
Quick Cost Comparison
| Material | Glazing | Estimated Price (Per Window) | Best For |
|---|---|---|---|
| uPVC | Double | £600 – £1,200 | Budget & Thermal Efficiency |
| Aluminium | Double | £1,200 – £2,200 | Modern Aesthetics & Strength |
| Timber | Double | £1,800 – £3,500 | Heritage & Character |
Regional Price Variance (Standard uPVC Double)
| Location | Price Range | Variance |
|---|---|---|
| London | £600 – £1,200 | Baseline |
| Manchester | £500 – £1,000 | -15% to -20% |
Performance Upgrade: Double vs Triple Glazing
| Specification | Price Delta | U-Value Impact | Typical Use Case |
|---|---|---|---|
| Double Glazing | Base | 1.2 - 1.6 | Standard UK Retrofit |
| Triple Glazing | +20% to 30% | 0.8 - 1.0 | Passivhaus / North-facing rooms |
What most guides miss: The “Hidden” 20%
Most online cost calculators ignore the installation failure rate and the VAT trap. You’ll often see “supply only” prices that exclude the £150-£300 per-window installation fee. More critically, if you are retrofitting an older property, you’re likely to hit structural rot in the reveals—a discovery that can add 20% to your final bill mid-project.
If you’re tackling a full-home retrofit, don’t just look at windows. Combining window upgrades with high-performance insulation and PV solar can radically shift your EPC rating. Check our Passivhaus spec guide or see how this integrates with IWantSolar for total energy autonomy. For those dealing with properties that are effectively Unmortgageable due to outdated glazing and damp, a strategic retrofit is the only way to recover asset value.
Next Steps
- Compare uPVC vs Timber costs
- Check Eco4 and Gbis eligibility for free replacements
- View the Passivhaus window specifications
Guides
- Bifold Door Cost UK: Aluminium vs uPVC Bifolds
- Composite Front Door Cost UK: Solidor, Rockdoor, and Apeer Pricing
- Conservation Area Windows: Article 4 Directions and Listed Building Consent
- Double vs Triple Glazing: EPC Uplift, Passivhaus Spec, and UK Price Delta
- ECO4, HUG2, and GBIS Eligibility: How to Get Free Windows and Insulation
- Passivhaus Windows Spec: U-value 0.80 or Lower and the Path to Zero Energy
- Sash Window Repair vs. Replace: Costs, Consent, and Conservation
- Secondary Glazing vs. Replacement: Acoustic and Thermal Trade-offs
- uPVC vs Timber vs Aluminium: Window Cost and Lifespan Comparison
- Velux Cost Guide: Roof Window Pricing, Sizing, and Alternatives