Quick Answer: What Does Double Glazing Cost in the UK?
The average cost of double glazing for a standard three-bedroom semi-detached house in the UK is around £6,000, including supply and professional installation. On a per-window basis, most homeowners pay between £400 and £700 for a standard uPVC casement window, fully fitted.
Those headline figures are drawn from aggregated quote data submitted to our comparison platform between January and April 2026, cross-referenced against published cost guides from Checkatrade and the Federation of Master Builders (FMB) HomePicks guide. Your final cost will depend on the type of windows you choose, the frame material, your property size, your location, and the time of year you book. This guide breaks down every variable so you can build an accurate budget before you speak to a single installer.
UK Context: The English Housing Survey 2024–25 (GOV.UK, January 2026) confirms that 89% of English homes now have full double glazing, up from 81% a decade ago. Yet the replacement market remains consistently active — glazing installations are dominated by retrofit work rather than new builds, meaning the vast majority of jobs involve replacing existing units rather than fitting windows for the first time. The UK DIY and decorating industry — of which glazing is a significant segment — generated an estimated £29.8 billion in revenue in 2024 (Hillarys/Statista, based on ONS data).
How We Calculated These Figures
The price ranges in this guide are based on three sources: anonymised quotes submitted to our comparison platform between January and April 2026; published cost benchmarks in the Federation of Master Builders HomePicks guide and Checkatrade; and energy and regulatory data from the Energy Saving Trust, FENSA, and GOV.UK Building Regulations. Where price ranges are given, the lower figure represents a straightforward retrofit using standard uPVC, and the upper figure reflects premium materials or more complex installations. All figures include VAT at 20%.
1. Cost by Window Type
Window style and mechanism directly affect manufacturing complexity and installation time — both of which feed into your quote.
Casement Windows
The UK’s most common window style, casement windows open on a side hinge and suit virtually every property type. They are available in every frame material and represent the baseline for double glazing pricing.
Typical cost (supply and fit): £400–£600 per window
Source: Aggregated installer quote platform data, Q1 2026; cross-referenced with FMB HomePicks guide.
For a detailed look at this popular style, see our guide to casement windows.
Sash Windows
Vertical sliding sash windows define Georgian and Victorian architecture and cost considerably more than casements due to the precision engineering required, the sliding mechanism, and — in many cases — the need to match heritage aesthetics.
Typical cost (supply and fit): £800–£1,400 per window
Timber sash windows sit at the upper end of that range. Modern uPVC sash windows offer a more affordable alternative without sacrificing the traditional appearance. If you’re weighing your options, our sash window dilemma guide explores this in depth.
Bay Windows
A bay window is typically three or more windows arranged at angles, often requiring a structural lintel and specialist fitting — pushing costs significantly higher than standard units.
Typical cost (supply and fit): £1,200–£3,500 per bay unit
The wide range reflects the number of panes involved and whether the bay is on an upper floor (which may require scaffolding) or sits at ground level.
Tilt-and-Turn Windows
Increasingly popular in modern and high-specification homes, tilt-and-turn windows open inward at the top for ventilation or swing fully open for cleaning and emergency egress.
Typical cost (supply and fit): £550–£900 per window
Our full guide to tilt-and-turn windows explains the mechanism and its benefits in detail.
2. Cost by Frame Material
Frame material is the single biggest determinant of your double glazing quote.
uPVC
uPVC is the dominant frame material in UK residential glazing. It is the most cost-effective option, requires almost no maintenance beyond an occasional clean, and performs well thermally. Modern uPVC is available in a wide range of colours and woodgrain foil finishes that convincingly replicate timber.
For more on uPVC’s evolution as a material, read our guide: The uPVC Evolution — Why Today’s Plastic Windows Are a Sustainable and Smart Choice.
Aluminium
Aluminium frames are considerably slimmer than uPVC, allowing for larger glass areas and a more architectural aesthetic. They are the premium choice for contemporary homes and extensions, and are exceptionally durable — a well-maintained aluminium window can last 40–45 years.
See our article on why aluminium windows are the future of energy efficiency for a fuller picture.
Timber
Timber is the traditional choice and remains the preferred option for period properties, conservation areas, and listed buildings. It requires the most maintenance — typically repainting or re-staining every five to eight years — but can last over 60 years with proper care. Historic England’s Advice Note 18 (July 2024), Adapting Historic Buildings for Energy and Carbon Efficiency, makes clear that where historic windows contribute to a listed building’s significance, retention and repair should always be assessed before replacement is considered.
Frame Material Price Comparison Table
| Frame Material | Cost per Window (Supply & Fit) | Lifespan | Maintenance | Best For |
|---|---|---|---|---|
| uPVC | £400–£700 | 20–35 years | Low (wipe clean) | Most UK homes; cost-conscious buyers |
| Aluminium | £700–£1,400 | 40–45 years | Low–medium | Modern/contemporary homes; large glazed areas |
| Timber | £900–£1,800 | 60+ years (with care) | High (regular repainting) | Period homes; conservation areas; listed buildings |
| Composite (timber-aluminium) | £1,000–£2,000 | 40+ years | Medium | Heritage aesthetics with lower maintenance |
Sources: Aggregated installer quote data and FMB HomePicks guide, Q1 2026. Figures include VAT at 20%. Lifespan range for uPVC per Energy Saving Trust.
For a head-to-head comparison, our uPVC vs Aluminium vs Timber material showdown is the definitive resource.
3. Cost by Property Type
The number of windows in your home is the primary driver of your total project cost. The figures below are based on standard uPVC casement windows at a mid-range price point.
| Property Type | Typical No. of Windows | Estimated Total Cost (uPVC) |
|---|---|---|
| 1-bed flat | 3–5 | £1,200–£3,000 |
| 2-bed terraced | 5–7 | £2,000–£4,200 |
| 3-bed semi-detached | 8–12 | £3,200–£7,200 |
| 3-bed detached | 10–14 | £4,000–£8,400 |
| 4-bed detached | 12–18 | £4,800–£10,800 |
| Bungalow (3-bed) | 7–10 | £2,800–£6,000 |
Source: Installer quote platform data, Q1 2026. Figures include VAT at 20%.
The £6,000 average for a three-bedroom house sits in the mid-range of the semi-detached bracket. Budget an additional 10–15% contingency on any figure you receive to cover unexpected complications such as deteriorated frames, structural issues, or ancillary building works.
Lead times: Once you have signed a contract with a FENSA-registered installer, a lead time of several weeks from order placement to installation is standard across the industry, driven by the manufacturing and delivery pipeline. Ask your installer for a specific timeframe at the point of quoting.
4. Regional Price Comparison
Labour rates, overhead costs, and competitive market conditions vary significantly across the UK. As a general rule, the further north and west you go, the more affordable glazing installation becomes — with London and the South East representing a meaningful premium.
| Region | Avg. Cost Per Window (uPVC Casement, Supply & Fit) | vs. UK Average |
|---|---|---|
| London (inner) | £550–£750 | +25–35% |
| South East (excl. London) | £480–£650 | +10–20% |
| South West | £440–£600 | +5–10% |
| East of England | £420–£580 | 0–5% |
| Midlands | £380–£530 | −5–10% |
| Yorkshire & Humber | £360–£510 | −8–12% |
| North West | £370–£520 | −8–12% |
| North East | £340–£490 | −10–15% |
| Scotland | £370–£530 | −5–10% |
| Wales | £360–£510 | −8–12% |
| Northern Ireland | £340–£480 | −10–15% |
Source: Installer quote data from the doubleglazingquote.net comparison platform, Q1 2026. These differentials are consistent with the regional labour cost patterns cited by the FMB HomePicks guide and Checkatrade. Figures include VAT at 20%.
Rural surcharges: If your property is more than 30–40 minutes from an installer’s base — common in rural Scotland, Wales, and parts of the South West — expect a travel or call-out surcharge of £50–£150 per visit.
5. Double Glazed Door Costs
Many homeowners replace doors and windows in a single installation visit, and there are often cost efficiencies in combining both jobs. Indicative costs by door type:
- uPVC front door (supply and fit): £700–£1,200
- Composite front door (supply and fit): £1,000–£2,000
- French doors (pair, supply and fit): £1,400–£2,500
- Bi-fold doors (3-panel, supply and fit): £2,500–£5,000
- Sliding patio doors (supply and fit): £1,200–£3,000
For a complete breakdown of all door types, styles, and materials, see our dedicated guide: Double Glazed Door Costs 2026: The Ultimate UK Pricing Guide.
6. Hidden Costs and Extras to Budget For
Scaffolding
If any windows are above ground floor level and cannot be safely accessed from inside, your installer may require a scaffold tower or full scaffolding. Expect to add £300–£800 to your budget if scaffolding is required. Always confirm whether this is included before signing.
Waste Removal
Your old windows need to be removed and disposed of responsibly. Some installers include skip hire in their quoted price; others do not. This can add £50–£200 to a full-house job if not included.
Building Regulations and FENSA Certification
Under GOV.UK Building Regulations, all replacement windows and doors in England and Wales must comply with Building Regulations — specifically Approved Document Part L (energy efficiency), Part K (safety glazing), and Part F (ventilation). FENSA’s guidance for homeowners confirms that from 15 June 2022 in England (and 23 November 2022 in Wales), the majority of replacement windows must also be fitted with trickle vents under Approved Document F, with exemptions for listed buildings and conservation areas.
As FENSA explains, it is a government-authorised Competent Person Scheme established in April 2002 that allows registered installers to self-certify compliance on your behalf — meaning you receive a FENSA certificate automatically, without a separate Local Authority Building Control (LABC) application. CERTASS is an alternative scheme offering equivalent compliance certification.
Without a FENSA or CERTASS certificate — or a LABC approval — for any window installation carried out after 1 April 2002, you may face complications when selling your home, as buyers’ solicitors routinely request proof of compliance.
A LABC application, if required, costs approximately £150–£250 and requires a building inspector to sign off the work.
Scotland and Northern Ireland: FENSA applies only in England and Wales. In Scotland, window replacements must comply with Scottish Building Standards under separate legislation. In Northern Ireland, separate Building Regulations approval is required. Always verify local requirements if you are outside England and Wales.
For everything you need to know about certification, see our explainer: FENSA and CERTASS Certificates: What Homeowners Need to Know.
Planning Permission
Under the Town and Country Planning (General Permitted Development) Order, most standard window replacements on houses in England do not require planning permission — they fall within Permitted Development rights, as confirmed by the Planning Portal. However, you will need to apply if:
- Your property is in a conservation area covered by an Article 4 Direction and you are changing the material or appearance of windows on a principal or road-facing elevation. Under Section 72 of the Planning (Listed Buildings and Conservation Areas) Act 1990, any development in a conservation area must preserve or enhance its character.
- Your home is a listed building — listed building consent is required for virtually all external alterations.
- You are changing windows in a flat — flats do not benefit from Permitted Development rights.
Historic England’s Advice Note 18 (July 2024) offers authoritative guidance on energy efficiency improvements in heritage buildings — and makes clear that measures including secondary glazing and draught-proofing are generally acceptable without listed building consent. Planning applications for domestic works cost £206 in England (2026 fee schedule), per the Planning Portal.
Lintel Replacement
If existing lintels are deteriorating, they may need replacing before new windows can be fitted. This can add £200–£600 per window opening in worst-case scenarios — a reputable surveyor will flag this before starting.
Internal Redecoration
New window frames are often slightly different in depth to the originals, which can leave small gaps or require re-plastering around reveals. Budget £50–£150 per window for minor internal finishing work if your property has plaster reveals rather than dry-lining.
7. Seasonal Pricing: When You Book Matters
Double glazing costs follow a predictable seasonal pattern. Spring and Summer (April–August) represent peak demand: installer diaries fill rapidly and prices tend to be higher than in off-peak months. Lead times also stretch during this period.
Autumn and Winter (October–February) is the off-peak window. Installers are more likely to negotiate, offer promotional pricing, or include extras such as waste removal at no additional cost. If your existing windows are not urgently failing and you have flexibility, booking in autumn or early winter can generate meaningful savings.
8. How to Save Money on Double Glazing
1. Get Multiple Quotes — Always
The single most effective saving is obtaining a minimum of three competitive quotes. Price variation between installers for identical specifications can be 20–30% or more. Use a comparison platform to streamline this process.
2. Replace All Windows in One Visit
Installers price jobs partly on fixed costs — travel, tools, disposal — spread across the total number of windows in the job. A 10-window project costs proportionally less per window than a 3-window project. Combining planned replacements into a single job will almost always save money overall.
3. Time Your Purchase for Off-Peak
Booking in autumn or early winter, when installer demand is lower, is one of the simplest ways to reduce your quote without changing any specification.
4. Explore Government Grants and Funding
Several funding routes are currently available to eligible UK homeowners:
- Great British Insulation Scheme (GBIS): Offers funding for insulation measures including glazing for households on means-tested benefits or in lower EPC bands.
- ECO4 (Energy Company Obligation): Administered through energy suppliers and can fund window upgrades for qualifying low-income households.
- Local Authority Flex (LA Flex): Councils can extend ECO4 funding to households not on benefits but experiencing fuel poverty — eligibility varies by council.
For a full breakdown of current grant eligibility and how to apply, see our guide: Double Glazing Grants 2026: Eligibility and Savings Explained.
5. Understand the VAT Position
Standard double glazing installation is subject to VAT at 20%. Despite the HMRC zero-rate relief for qualifying energy-saving materials (currently 0% until 31 March 2027), replacement windows and doors are specifically not included on the qualifying list (section 2.18 of HMRC VAT Notice 708/6). This is an important detail that many homeowners and even some installers overlook. All prices in this guide already include VAT at 20%.
6. Consider Finance Options
Many reputable installers offer 0% or low-interest finance. Our guide to window finance options sets out what to look for and what to avoid. For independent advice on financing home improvements, MoneySavingExpert is a useful starting point.
7. Match Specification to Your Property
Premium aluminium or timber frames add limited return on investment in a standard 1990s semi-detached. Match your specification to your property type, energy efficiency goals, and resale ambitions. See our ROI analysis for detailed figures.
9. Energy Savings: What to Realistically Expect
According to the Energy Saving Trust, upgrading from single-glazed windows to A-rated double glazing in a typical entirely single-glazed semi-detached home can save £140 per year on energy bills in Great Britain, with a reduction of approximately 380kg of CO₂ annually. These are the Energy Saving Trust’s own published figures for a semi-detached home; savings for larger or smaller properties will differ.
The GGF’s Window of Opportunity report (2023) adds further context: replacing older double glazing that predates the 2002 Building Regulations changes with new windows meeting current standards can reduce heat loss in an already-insulated home from 44% to 22% — a 50% improvement in thermal performance.
On the technical side, a standard double-glazed unit achieves a U-value of approximately 1.2–1.4 W/m²K, well below the single-glazing benchmark of around 5.0 W/m²K. UK Building Regulations Approved Document L requires replacement windows in existing dwellings to achieve a minimum of 1.6 W/m²K, meaning modern double glazing comfortably exceeds the regulatory minimum.
For period or listed properties where full replacement is not appropriate, Historic England’s research on secondary glazing confirms that secondary glazing with a low-emissivity (Low-E) coating can reduce heat losses through a window by over 60% — making it a highly effective and often consent-free alternative. Their Advice Note 18 (July 2024) provides the definitive guidance on works acceptable in listed buildings.
For the triple glazing comparison, see our dedicated guide: Triple Glazing vs Double Glazing: Is It Worth It?
10. Using Our Double Glazing Cost Calculator
Our Double Glazing Cost Calculator gives an instant indicative estimate based on your inputs: property type, number of windows, preferred frame material, UK region, and any door replacements.
Be specific about window types. Input casements and bay windows separately — they carry very different costs.
Use it for ballpark guidance, not final budgeting. The calculator generates estimates based on market averages. Your actual quoted price may differ based on access complexity, existing frame condition, and installer overhead.
Use the output as a benchmark. If quotes you receive are significantly above the estimate, ask installers to itemise the difference.
Then get real quotes. Once you have a realistic ballpark, use our comparison service to receive quotes from FENSA-registered local installers.
11. Frequently Asked Questions
How much does it cost to replace all windows in a 3-bedroom house in the UK?
The commonly cited average is approximately £6,000 for a standard three-bedroom semi-detached or terraced house using mid-range uPVC casement windows, based on aggregated installer quote data. Costs range from around £3,500 for a budget installation to £9,000+ for premium aluminium or timber frames. Always obtain at least three quotes from FENSA-registered installers and allow a 10–15% contingency.
What is the cheapest type of double glazing?
Standard uPVC casement windows, typically costing £400–£600 per window supply and fit. uPVC is the dominant frame material in UK residential glazing, combining low cost with solid thermal performance and minimal maintenance.
Do I need planning permission for replacement double glazing?
In most cases, no. For houses in England, window replacements fall within Permitted Development rights under the Town and Country Planning (General Permitted Development) Order. Exceptions include listed buildings, flats, and properties in conservation areas with an Article 4 Direction. Always check with the Planning Portal or your Local Planning Authority if in doubt.
What is FENSA and why does it matter?
FENSA (Fenestration Self-Assessment Scheme) is a government-authorised Competent Person Scheme, established in April 2002, that allows registered window and door installers in England and Wales to self-certify compliance with Building Regulations. When you use a FENSA-registered installer, they register the installation with your local council on your behalf, and you receive a FENSA certificate — an important legal document you will need when selling your property.
Is double glazing installation subject to VAT?
Yes, at the standard rate of 20%. Despite the HMRC zero-rate relief for energy-saving materials (0% until 31 March 2027), replacement windows are not included on the qualifying list (HMRC VAT Notice 708/6, section 2.18). All prices in this guide include VAT at 20%.
How long does double glazing last?
According to the Energy Saving Trust, double glazed windows can last 20 to 35 years if they are high-quality, installed properly, and well maintained — and can last well beyond 35 years with regular care. Signs that replacement may be needed include condensation between panes (indicating a failed seal), draughts, difficulty opening or closing, or visible frame deterioration. If only the sealed unit has failed, replacing just the glass is often a more cost-effective solution.
What are the minimum energy performance standards for replacement windows?
Under UK Building Regulations Approved Document L, replacement windows in existing dwellings must achieve a minimum whole-window U-value of 1.6 W/m²K. Standard double-glazed uPVC windows typically achieve 1.2–1.4 W/m²K, comfortably exceeding this minimum.
Figures at a Glance
| Claim | Figure | Source |
|---|---|---|
| Average cost, 3-bed house (uPVC) | ~£6,000 | Aggregated installer quote data, Q1 2026; FMB HomePicks |
| Cost per window, supply and fit | £400–£600 | Aggregated installer quote data, Q1 2026; Checkatrade |
| Energy saving, single→A-rated DG (semi-detached) | £140/yr | Energy Saving Trust |
| CO₂ reduction (semi-detached) | 380 kg/yr | Energy Saving Trust |
| Double glazed window lifespan | 20–35 years (up to 35+ with care) | Energy Saving Trust |
| % English homes with full double glazing | 89% | English Housing Survey 2024–25, GOV.UK (Jan 2026) |
| Min. U-value, replacement windows (existing dwellings) | 1.6 W/m²K | Building Regulations Approved Document L |
| Typical U-value, standard uPVC double glazing | 1.2–1.4 W/m²K | Building Regulations / industry standard |
| VAT rate on DG installation | 20% | HMRC VAT Notice 708/6 |
| Secondary glazing heat-loss reduction (with Low-E) | 60%+ | Historic England |
| UK DIY & decorating industry revenue (2024) | £29.8 billion | Hillarys/Statista, based on ONS data |
| Heat loss reduction, pre-2002→current standard DG | 44%→22% | GGF Window of Opportunity report, 2023 |
| FENSA scheme established | April 2002 | FENSA |
| Trickle vent requirement in force | 15 June 2022 (England) | FENSA / Approved Document F |
All prices verified April 2026. All prices include VAT at 20%. Regional variations apply — see Section 4 for the full regional breakdown.
Sources Referenced in This Guide
- Energy Saving Trust — Windows and Doors
- GOV.UK Building Regulations Approval
- HMRC VAT Notice 708/6 — Energy-Saving Materials
- FENSA — About FENSA
- FENSA — Building Regulations for Homeowners
- CERTASS
- Glass and Glazing Federation (GGF) — Window of Opportunity report, 2023
- Historic England — Adapting Historic Buildings for Energy and Carbon Efficiency (Advice Note 18, July 2024)
- Historic England — Secondary Glazing for Windows
- Planning Portal — Planning Permission
- Planning (Listed Buildings and Conservation Areas) Act 1990
- English Housing Survey 2024–25, GOV.UK
- Federation of Master Builders — HomePicks Windows Cost Guide
- Hillarys UK Home Renovation Statistics
- Which? — Windows Guide
- MoneySavingExpert
- GreenMatch — Windows
This guide was produced by the editorial team at doubleglazingquote.net. Price data is aggregated from installer quotes submitted to our comparison platform and cross-referenced against published benchmarks from the Federation of Master Builders, Checkatrade, and regulatory guidance from the Energy Saving Trust, FENSA, and GOV.UK Building Regulations. We update this guide quarterly. Last updated: April 2026.
