Double Glazing Costs in the UK The Complete 2026 Pricing Guide

Prices verified April 2026 | Sources: Energy Saving Trust, FENSA, Glass and Glazing Federation, GOV.UK Building Regulations, Historic England

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 £600 for a standard uPVC casement window, fully fitted.

Those are the headline figures — but the real answer depends significantly on what you choose. Your final cost will be shaped by window type, frame material, property size, location, and even 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: According to industry data, 93% of UK homes now have double glazing, yet the retrofit market remains highly active — at a 3:1 ratio of retrofits to new builds, there are far more replacement jobs underway than new installations at any given time. The UK home improvement sector is valued at £29.7 billion (Statista / DESNZ), with glazing one of its most significant segments.

How We Calculated These Figures

The price ranges in this guide are drawn from three sources: anonymised quotes submitted to our comparison platform between January and April 2026; published installer price lists from FENSA-registered companies across all UK regions; and pricing benchmarks published by the Glass and Glazing Federation (GGF) and cross-referenced against Energy Saving Trust guidance. Where 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: GGF benchmark data; doubleglazingquote.net installer platform, Q1 2026.

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. They 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 decision 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. They are particularly common in apartment buildings.

Typical cost (supply and fit): £550–£900 per window

Our full guide to tilt-and-turn windows explains the mechanism, benefits, and typical applications.

2. Cost by Frame Material

Frame material is the single biggest determinant of your double-glazing quote.

uPVC

uPVC accounts for approximately 75% of the UK window market by volume (GGF, 2025). Its dominance reflects strong practical advantages: 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) acknowledges that where historic windows make a positive contribution to a listed building’s significance, retention and repair should always be explored before replacement.

Frame Material Price Comparison Table

Frame Material	Cost per Window (Supply & Fit)	Lifespan	Maintenance	Best For
uPVC	£400–£700	20–30 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: GGF pricing benchmarks; doubleglazingquote.net installer platform data, Q1 2026. Figures include VAT at 20%.

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

The £6,000 average for a three-bedroom house cited consistently across the industry 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, expect a 6–12 week lead time from order placement to installation. This is driven by the manufacturing and delivery pipeline and is standard across the industry.

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: Regional installer data compiled via doubleglazingquote.net comparison platform, Q1 2026. 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. Double-glazed door costs vary considerably 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, materials, and security ratings, see our dedicated guide: Double Glazed Door Costs 2026: The Ultimate UK Pricing Guide.

6. Hidden Costs and Extras to Budget For

One of the most common sources of budget shock in home improvement projects is the gap between a headline quote and the final invoice. Here are the additional costs most commonly missed.

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 in your quote 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

According to GOV.UK Building Regulations guidance, 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 — including mandatory trickle vents in most replacement scenarios from June 2022 onwards, per FENSA’s Building Regulations guidance for homeowners).

The simplest route to compliance is using a FENSA-registered or CERTASS-registered installer. As FENSA explains, these are government-authorised Competent Person Schemes that allow 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.

If you use a non-registered installer, a LABC application will cost approximately £150–£250 and requires a building inspector to sign off the work. Without either a FENSA certificate or LABC approval, you may face complications at the point of sale — buyers’ solicitors routinely request proof of compliance for any window installation carried out after 1 April 2002.

For everything you need to know about certification, see our explainer: FENSA and CERTASS Certificates: What Homeowners Need to Know.

Scotland and Northern Ireland: FENSA applies only in England and Wales. In Scotland, window replacements must comply with Scottish Building Standards. In Northern Ireland, Building Regulations approval is required through separate legislation. Always check local requirements if you are outside England and Wales.

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. 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, and in many cases internal ones too.
You are changing windows in a flat — flats do not benefit from Permitted Development rights, so any external change requires planning permission.

Historic England’s Advice Note 18 (July 2024), Adapting Historic Buildings for Energy and Carbon Efficiency, offers authoritative guidance on navigating energy efficiency improvements in listed and heritage buildings — and makes clear that many improvements, 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 (the structural beams above window openings) are deteriorating, they may need replacing before new windows can be fitted. This structural work can add £200–£600 per window in worst-case scenarios — a reputable surveyor will flag this before starting.

Internal Redecoration

New window frames are often slightly different in depth or profile 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 labour rates can run 10–20% higher than in off-peak months. Lead times also stretch during this period, sometimes to 12 weeks or beyond.

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 on the same specification.

Pricing context: Industry data indicates that renovation costs dropped approximately 25% from their 2023 peak, largely due to supply chain normalisation and the easing of post-pandemic labour shortages. That correction makes 2026 a genuinely favourable time to invest in window replacement compared to pricing at the recent peak.

8. How to Save Money on Double Glazing

1. Get Multiple Quotes — Always

The single most effective saving available to any homeowner 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 number of windows in the job. A 10-window project costs proportionally less per window than a 3-window project. If you planned to phase replacements over several years, combining them into a single job will almost always save money overall.

3. Time Your Purchase for Off-Peak

Booking in autumn or early winter can reduce costs by 10–20%, as detailed above. If your existing windows are not urgently failing, this is an easy saving.

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, this scheme 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 dedicated guide: Double Glazing Grants 2026: Eligibility and Savings Explained.

5. Understand the VAT Position

Standard double-glazing installation is subject to VAT at the standard rate of 20%. Unlike insulation, heat pumps, and solar panels, which qualify for the GOV.UK VAT zero rate on energy-saving materials (currently 0% until 31 March 2027, per HMRC guidance) — replacement windows and doors are not on the qualifying list of energy-saving materials and do not benefit from the relief. All prices in this guide include VAT at 20%.

6. Consider Finance Options

Many reputable installers offer 0% or low-interest finance on window installation. If managed responsibly, spreading the cost over 12–36 months can make a full-house replacement achievable without depleting savings. Our guide to window finance options sets out what to look for — and what to avoid. For further independent advice, MoneySavingExpert offers a useful consumer perspective on financing home improvements.

7. Match Specification to Your Property

While premium aluminium or timber frames are appropriate for high-value period homes, they 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 double glazing installations for detailed figures.

9. Energy Savings: What to Realistically Expect

Understanding the financial case for double glazing is an important context for any investment decision.

According to the Energy Saving Trust, upgrading single-glazed windows to A-rated double glazing can save around £140 per year on energy bills in a typical home in Great Britain, along with a reduction of approximately 380kg of CO₂ emissions annually. In a semi-detached home, savings of £175–£235 per year are achievable. For larger detached properties, the Energy Saving Trust notes potential savings can reach £110–£350 per year, depending on property size, current glazing, and the specification installed.

According to the GGF, replacing single-glazed windows with modern double glazing in a semi-detached home can yield annual savings of up to £195 at today’s energy prices.

On the thermal performance side, a standard double-glazed unit achieves a U-value of 1.2–1.4 W/m²K, significantly better than the 5.0 W/m²K typical of single glazing. UK Building Regulations Approved Document L sets a minimum standard of 1.6 W/m²K for replacement windows in existing dwellings — meaning modern double glazing comfortably exceeds the minimum requirement.

Historic England research notes that where full double glazing replacement is not appropriate — for example, in listed buildings — secondary glazing with a low-emissivity coating can reduce heat losses through a window by over 60%, making it a highly effective alternative (Historic England).

For more on whether triple glazing is worth the additional investment, 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 specific inputs: property type, number of windows, preferred frame material, UK region, and any door replacements. Here’s how to get the most from it:

Be specific about window types. If you have a mix of casements and one bay window, input them separately rather than treating them as equivalent units.

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 the quotes you receive are significantly above the calculator’s estimate, ask installers to itemise the difference. Legitimate reasons exist — but so do inflated margins.

Then get real quotes. The calculator is the starting point, not the endpoint. Once you have a realistic ballpark figure, 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 national average for a full window replacement in a standard three-bedroom semi-detached or terraced house is approximately £6,000, using mid-range uPVC casement windows. 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 are the most affordable double-glazing option in the UK, typically costing £400–£600 per window, supply and fit. uPVC accounts for approximately 75% of the UK market (GGF, 2025) because it combines 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 your Local Planning Authority or consult the Planning Portal if you are unsure.

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 that their work complies 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. Standard double glazing installation attracts VAT at the full 20% rate. Despite the HMRC zero-rate relief for energy-saving materials (currently 0% until 31 March 2027), replacement windows are not included on the qualifying list of energy-saving materials. All prices quoted in this guide include VAT at 20%.

Does double glazing add value to my home?

Yes. Double glazing improves your property’s Energy Performance Certificate (EPC) rating, which is increasingly important to buyers and mortgage lenders. Studies suggest a well-executed installation can add up to 10% to a property’s value, with the Energy Saving Trust noting that improving your EPC can have a tangible effect on property desirability. See our full ROI analysis for detailed figures.

What are the minimum energy performance standards for replacement windows?

UK Building Regulations Approved Document L requires replacement windows in existing dwellings to achieve a minimum U-value of 1.6 W/m²K (whole window). Standard double-glazed uPVC windows typically achieve 1.2–1.4 W/m²K, comfortably exceeding this minimum. Premium double-glazed units can reach 1.0–1.2 W/m²K, while triple glazing achieves 0.8 W/m²K.

How often should double glazing be replaced?

A well-made and properly installed uPVC double glazing unit will last 20–30 years according to Energy Saving Trust guidance, and can last beyond 35 years with good maintenance. Signs that replacement is overdue include failed seals (visible condensation between panes), draughts, difficulty opening or closing, or visible frame deterioration. If only the sealed unit has failed rather than the frame, replacing just the glass is often a cost-effective solution.

Summary: Key Figures at a Glance

Data Point	Figure	Source
Average cost, 3-bed house (uPVC)	£6,000	GGF / installer platform data
Cost per window, supply and fit	£400–£600	GGF / installer platform data
Energy bill saving (single→A-rated DG)	£140–£235/yr	Energy Saving Trust
CO₂ reduction (semi-detached)	380 kg/yr	Energy Saving Trust
Min. U-value for replacement windows	1.6 W/m²K	Building Regulations Approved Doc L
Price drop since 2023 peak	~25%	Industry pricing data
Summer labour premium	10–20%	Seasonal installer survey
Recommended contingency	10–15%	Building industry standard
Typical lead time	6–12 weeks	Installer operations data
uPVC market share	~75%	Glass and Glazing Federation
UK homes with double glazing	93%	DESNZ housing stock data
Retrofit-to-new-build ratio	3:1	FENSA registration data
UK home improvement sector value	£29.7 billion	Statista / DESNZ
VAT rate on DG installation	20%	HMRC
Secondary glazing heat-loss reduction	60%+	Historic England

All figures 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

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 benchmarks from the Energy Saving Trust, the Glass and Glazing Federation, FENSA, and Building Regulations guidance documents. We update this guide quarterly. Last updated: April 2026.