The cost of replacing all windows and doors in a typical three-bedroom semi-detached house in the UK is between £7,500 and £12,500 for double glazing, rising to £9,000–£16,000 for triple glazing, according to the Government’s Energy Performance Certificate guidance (2026). This figure includes supply and standard installation of eight windows and two external doors.
The final price depends heavily on frame material, glass type, finish, and property size. uPVC is the most affordable option, aluminium and timber are more expensive. Listed buildings or homes in conservation areas may require bespoke or heritage-style units, which can double the cost. Labour, waste removal, and any structural work for oversized openings also add to the total. Always obtain at least three itemised quotes from TrustMark-registered installers.
Frame material and glass type set the price range
uPVC double-glazed windows cost £300–£600 per window fitted, while composite doors range from £800–£1,500 each (Energy Saving Trust, 2026). Aluminium frames are 30–50% more expensive, with windows at £500–£1,200 each and doors at £1,200–£2,500. Timber frames are the premium choice, starting at £700 per window and £1,800 per door. Triple glazing adds roughly 20–30% to the cost of any frame material. Low-emissivity (low-E) glass and argon gas filling are standard for new double glazing and do not increase the price significantly.
Energy efficiency grants can reduce your outlay
The Great British Insulation Scheme closed on 31 March 2026. It funded insulation measures only and never covered windows or glazing. Eligibility is means-tested and typically requires a home energy assessment first. The Energy Company Obligation (ECO4) also funds replacement windows and doors for low-income households, with installers managing the paperwork. Without grants, the payback period from energy savings alone is unlikely to be under 15 years, so prioritise comfort and property value gains.
Installation costs and hidden extras add 10–20%
Removal of old windows and doors, skip hire, and making good internal plaster typically add £500–£1,500 to a full-house project (FENSA, 2026). If your property has non-standard brickwork or requires lintel reinforcement, expect an additional £200–£400 per opening. All installations affecting the building envelope must comply with Building Regulations Part L, and you should use a FENSA-registered or CERTASS-registered installer to self-certify the work. Always confirm whether the quote includes VAT at 20%, some installers quote ex-VAT and add it later.
A worked example
Glazing is standard-rated for VAT at 20%. The zero rate for energy-saving materials covers insulation, heat pumps and solar panels; HMRC names secondary and double glazing as excluded (VAT Notice 708/6). This price is based on mid-range A-rated units from a TrustMark-registered installer, including standard white frames, trickle vents, and removal of the old single-glazed windows and timber doors. The Energy Saving Trust estimates that upgrading from single glazing to A-rated double glazing saves a semi-detached home roughly £195 per year on heating bills. With the upfront cost at £9,400, the simple payback period works out at 48 years, which is longer than the windows’ expected lifespan. However, the real value comes from comfort, reduced condensation, and a potential 10–15% increase in the property’s EPC rating. If the same home were in a conservation area requiring heritage-style timber windows, the cost would rise to around £16,500 and the payback would extend beyond 60 years.
| Item | Figure |
|---|---|
| Upfront cost after grants | £9,400 |
| Yearly savings | £195 |
| Payback period | 48 years |
| 25-year lifetime savings | £4,875 |
What homeowners often get wrong
The most common mistake is choosing the cheapest quote without checking the glass specification or installation guarantees. Here are three frequent errors that cost UK homeowners money and comfort.
- Assuming all double glazing is the same A standard 4-16-4 double-glazed unit (two 4mm panes with a 16mm gap) performs far worse than a warm-edge 4-20-4 unit with argon gas fill. The cheaper option can lose 25% more heat, adding roughly £60 to your annual heating bill and reducing your EPC score by up to 10 points.
- Skipping the trickle vents Many homeowners reject trickle vents on new windows because they look ugly or let in draughts. Without them, a modern airtight home can develop condensation, black mould, and rot in window frames within 12 months. Replacing a mould-damaged uPVC frame costs £200–£400 per window, far more than the £30 per vent saved.
- Ignoring FENSA or CERTASS registration Hiring an unregistered installer saves maybe £200 on the quote but means the work is not certified under Building Regulations. When you sell the house, the buyer’s solicitor will demand retrospective building control approval, which costs £400–£800 and can delay the sale by eight weeks.
Quick reference
- A full set of eight uPVC double-glazed windows and two composite doors for a three-bed semi costs £7,500–£12,500 installed, according to Energy Performance Certificate guidance.
- Triple glazing adds 20–30% to the cost of any frame material but only improves the U-value by roughly 0.3 W/m²K compared to modern double glazing.
- You can check your installer’s registration on the TrustMark, FENSA, or CERTASS website before paying a deposit.
- Glazing is standard-rated for VAT at 20%. The zero rate for energy-saving materials covers insulation, heat pumps and solar panels; HMRC names secondary and double glazing as excluded (VAT Notice 708/6).
- Never accept a quote that does not include the removal and disposal of old windows and doors, skip charges can add £400–£800 later.
Frequently Asked Questions
For a typical three-bedroom semi-detached house, expect £7,500–£12,500 for double glazing or £9,000–£16,000 for triple glazing. The Energy Saving Trust confirms uPVC is the most affordable frame option.
uPVC double-glazed windows cost £300–£600 each fitted, and composite doors range from £800–£1,500 each according to the Energy Saving Trust (2026). Prices vary by size and finish.
Yes, if your home is in a cold or noisy area. Triple glazing adds 20–30% to the cost, but can reduce heat loss by up to 30% compared to double glazing, says the Government's EPC guidance.
