How much does double glazing cost per window in the UK?

Supply and fit prices sit between £450 and £1,250 per window for most homes in 2026. Larger openings, premium glazing or heritage sash windows push costs higher. Standard white uPVC casements are at the lower end of this range.

How much does it cost to double glaze a whole house?

For a full set of uPVC double-glazed windows, a two-bedroom flat costs £2,000 to £4,000, a three-bedroom semi costs £4,000 to £8,000, a four-bedroom detached costs £8,000 to £15,000, and a Victorian terrace costs £6,000 to £12,000. Timber windows cost 50 to 100 percent more.

Is it worth upgrading to triple glazing?

For most UK retrofits, A-rated double glazing delivers the vast majority of available thermal improvement at a significantly lower cost than triple glazing. Triple glazing makes most sense in new builds, high-specification renovations or properties where noise reduction is a primary concern alongside thermal performance.

Does double glazing add value to a property?

New double-glazed windows typically add 5 to 10 percent to a property's value. For a £350,000 home, that is a potential increase of £17,500 to £35,000, usually exceeding the installation cost. New windows also improve EPC ratings and make properties more attractive to buyers.

What is FENSA and why does it matter?

FENSA is a government-authorised scheme that allows registered installers to self-certify that window replacements comply with Building Regulations. A FENSA certificate is essential for future property sales. Always confirm your installer is FENSA or CERTASS registered before signing a contract.

Home & Property

Double Glazing Cost Calculator UK

Enter your window style, frame material, number of windows and property type to instantly estimate the cost of double glazing, whether you are replacing individual windows or budgeting for a whole-house installation.

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How Much Does Double Glazing Cost in the UK?

For a standard three-bedroom UK property with six to eight windows, a realistic installed price range is £3,000 to £7,000. The exact figure depends on window style, frame material, glazing specification and access requirements. Here is a quick reference by property size:

Property Size	Typical Windows	uPVC Double Glazing (Installed)	1–2 bedroom flat
4–6	£2,000 – £4,000	3-bedroom semi-detached	8–10
£4,000 – £8,000	3-bedroom detached	10–12	£5,000 – £9,000
4-bedroom detached	12–14	£8,000 – £15,000	Victorian terrace
8–12	£6,000 – £12,000	All figures include supply, installation, VAT, and disposal of old frames. Prices stabilised in 2026 to 2027 with most installers holding or making only modest increases of 2 to 4 percent as supply chains normalised following post-pandemic disruption.

Double Glazing Cost Per Window by Style

Window style has the biggest impact on per-unit cost. Casement windows are the market baseline because manufacturing is standardised and fitting is straightforward in most properties.

Window Cost per Unit by Style & Material

Window Style	uPVC (Installed)	Aluminium (Installed)	Timber (Installed)
Casement	£350 – £800	£600 – £1,400	£800 – £1,500
Tilt and turn	£500 – £1,100	£600 – £1,200	£900 – £1,600
Sash (sliding)	£600 – £1,200	£900 – £1,800	£1,200 – £2,800
Bay (3-panel)	£1,500 – £3,500	£2,500 – £5,000	£3,000 – £6,000+
Georgian bar	£800 – £2,000	£1,000 – £2,500	£1,500 – £3,500

Bay windows involve more complex framing and longer fitting times. If the existing bay structure needs reinforcement or the roof above needs work, structural costs of £500 to £1,500 may apply on top. Always get a survey before committing to a bay window replacement quote.

Frame Materials: uPVC, Aluminium or Timber?

Frame material is the single biggest variable in your double glazing quote. Understanding the trade-offs helps you choose the right specification for your property.

uPVC is the most popular choice in the UK and the most affordable. When factoring total cost of ownership over 25 years, uPVC remains the most economical choice: approximately £4,500 upfront with virtually zero maintenance, versus £12,000 upfront plus £2,500 to £7,500 in maintenance for timber. White uPVC is cheapest; coloured finishes such as anthracite grey or chartwell green add £50 to £100 per window.

Aluminium offers a slimline, contemporary appearance and suits modern properties well. Aluminium costs approximately 25% more than uPVC but 25% less than timber frames. It requires very low maintenance and is particularly popular for larger openings and bi-fold configurations.

Timber is the premium option and the right choice for period properties, listed buildings and conservation areas. Timber frames have the longest potential lifespan at 60 or more years with diligent maintenance but require repainting or re-staining every three to five years to prevent rot. Fitting uPVC in a period property instead of timber can decrease the property's value and turn off buyers.

Double Glazing vs Triple Glazing

Triple glazing adds a third pane of glass and a second insulating gas-filled cavity. Expect to add £150 to £350 per window on top of the equivalent double-glazed price for triple glazing.

For most UK homes, the additional thermal gain from triple glazing is modest compared to the premium. Triple glazing makes the most sense in new builds designed to Passivhaus or high-specification standards, properties in colder northern regions or homes where noise reduction is a priority alongside thermal performance. For a standard retrofit on a mid-terrace or semi-detached, A-rated double glazing delivers the majority of available energy savings at a significantly lower outlay.

Glazing Upgrades

Beyond the basic double-glazed unit, several upgrades affect both performance and cost:

Low-E glass coating: applies a thin metallic layer that reflects heat back into the room, improving thermal performance without adding visible thickness. Standard on most A-rated units.
Argon gas fill: replaces air in the cavity between panes with argon, which conducts heat less efficiently. Standard on most mid-range and above specifications.
Acoustic glass: uses a thicker inner pane to reduce noise transmission. Worth considering for properties on busy roads or near airports. Adds approximately £50 to £150 per window.
Toughened or laminated safety glass: required by Building Regulations in windows near floor level, doors and certain bathroom locations.

Additional Costs to Budget For

A transparent quote should show frame type, glass specification, opening style, trickle vents, installation, finishing and waste removal as distinct lines. These additional items are frequently omitted from headline quotes:

Scaffolding: Required for upper-floor windows on most properties above ground level. Expect £500 to £1,500 extra depending on scale.
Coloured frame finishes: Anthracite grey, black or woodgrain finishes increase costs by 20 to 40 percent over standard white uPVC and often carry longer lead times.
Disposal of old frames: Some installers include this; others charge separately. Confirm in writing.
Interior finishing: Plaster repairs, window board replacement, or decorating after installation are rarely included in a standard glazing quote.
FENSA or CERTASS certification: A FENSA certificate is essential for future property sales. If your installer is not registered, separate Building Control approval costs £200 to £400.

Energy Bill Savings from Double Glazing

Replacing single-glazed windows with A-rated double glazing saves around £140 per year on energy bills for a semi-detached home, according to the Energy Saving Trust. A-rated double glazing can lower heating demand enough to save around £150 to £200 per year in a typical three-bedroom home, while also improving comfort and reducing condensation risk.

The payback period on a full double glazing installation at these savings rates is typically 15 to 25 years, meaning double glazing is better justified by comfort, noise reduction, property value and EPC improvement than by energy savings alone.

Double Glazing Grants UK 2026

There are several grants in the UK for energy-efficient home improvements that cover double glazing, including the ECO4 scheme, the Warm Homes Local Grant and the Home Energy Scotland Loan. They can help with up to 100% of the cost of double glazing but you have to meet certain eligibility criteria.

The ECO4 scheme is available to households on qualifying benefits or low incomes and is delivered through energy suppliers. The Warm Homes: Local Grant replaced the Home Upgrade Grant (discontinued March 2025) and is allocated through local authorities. If you are on a low income or receiving means-tested benefits, check eligibility before paying for double glazing out of pocket.

Planning Permission and Building Regulations

Double glazing replacement does not require planning permission in most cases, it falls under permitted development. Exceptions apply to listed buildings and properties in conservation areas, where you may need to match original window styles and materials.

Building Regulations do apply to window replacement to ensure minimum thermal performance (U-value 1.4 W/m²K for replacement windows) and safety glass requirements. FENSA or CERTASS registered installers self-certify compliance automatically. If your installer is not registered with either scheme, you will need to notify your local authority Building Control separately.

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