TL;DR: Double glazing costs between £400 and £850 per window installed, depending on frame material, style, and what the quote actually includes. Whole-house costs run from around £4,900 for a 2-bed property to £10,500 for a 4-bed. Use Apex’s instant online calculator to get a real price for your home in under 10 seconds.
Double glazing rarely lands at the top of a to-do list until something forces the issue. Condensation sitting between the panes. A draught that wasn’t there last winter. A house move that’s made you look at the windows properly for the first time in years.
Once you’re at that point, the first question is always the same: what’s this going to cost? This post answers it with real figures, broken down by window style, frame material, and property size.
Double Glazing Cost at a Glance
Standard uPVC casement windows cost between £400 and £850 per window, fully installed. Sash and bay windows cost more because of their mechanisms and fitting time. Frame material is the single biggest variable: aluminium runs roughly 50% more than uPVC, timber more again.
All figures below include supply, installation, and VAT. No hidden extras.
Cost by Window Style
Window style | Low | Average | High |
Casement (uPVC) | £400 | £600 | £850 |
Tilt and turn (uPVC) | £450 | £650 | £900 |
Sliding sash (uPVC) | £600 | £850 | £1,100 |
Bay window (uPVC) | £1,000 | £1,400 | £1,800 |
Cost by Frame Material
Frame material | Typical fitted cost per window |
uPVC | £400 to £850 |
Aluminium | £600 to £1,300 |
Timber | £800 to £1,600 |
Per-m2, standard uPVC double glazing runs approximately £150 to £300 installed. Aluminium sits between £400 and £600 per m2, depending on specification. Most installers quote per window rather than per m2, so treat those figures as rough reference points rather than the basis for a final budget.
All our fitters are directly employed and every quote includes VAT and fitting with no hidden additions. Every installation is covered by a 10-year insurance-backed guarantee through InstallSure, and Apex is FENSA registered. The price from Apex’s online calculator is what you pay.
How Much Does It Cost to Double Glaze a Whole House?
Whole-house double glazing costs depend on how many windows your property has, not bedroom count. A typical 2-bed house has 6 to 8 windows, a 3-bed has 8 to 12, and a 4-bed has 12 to 16. On standard uPVC casement windows from a FENSA-registered installer with all costs included, that translates to roughly £4,900 to £12,000 depending on property size and specification.
Property size | Typical window count | Apex price (inc. VAT & fitting) | Wider market range |
2-bed house | 6 to 8 windows | From £4,914 | £2,500 to £4,500 |
3-bed house | 8 to 12 windows | From £7,480 | £4,000 to £7,000 |
4-bed house | 12 to 16 windows | From £10,472 | £6,500 to £10,000 |
Cost of Double Glazing a 2-Bed House
A 2-bed house typically has 6 windows. Across the market, that runs from £2,500 to £4,500 depending on the installer, specification, and what the quote includes. From a FENSA-registered installer with VAT and fitting included, expect to pay toward the upper end of that range. Apex’s figure for 6 windows is £4,914, all-in.
A terraced 2-bed will usually have fewer windows than a semi-detached one, so window count matters more than bedroom count when you’re budgeting.
Cost of Double Glazing a 3-Bed House
Across the market, a 3-bed costs between £4,000 and £7,000 according to expertsure.com, with around 10 windows as the typical baseline. From a FENSA-registered installer with all costs included, expect to sit toward the upper end of that range. Apex’s figure for 10 windows is £7,480.
If your property has a bay window or sash windows rather than standard casements, expect the total to rise accordingly.
Cost of Double Glazing a 4-Bed House
Detached and semi-detached 4-beds can vary significantly in window count, which is why the market range of £6,500 to £10,000 (expertsure.com) is wider here than for smaller properties. From a FENSA-registered installer with all costs included, expect to sit at the top of that range or above it. Apex’s figure for 14 windows is £10,472.
Upper-floor access can also affect installation cost on larger properties, so it’s worth raising with any installer before you commit to a quote.
What Affects the Cost of Double Glazing?
The gap between a £400 window and a £1,500 window comes down to four factors: frame material, window style, glazing specification, and installation complexity. Understanding each one makes it easier to read a quote accurately.
Frame Material
Frame material has the biggest single impact on price. uPVC is the most common choice for UK homes and the most affordable, typically £400 to £850 per window installed. Aluminium costs roughly 50% more for the same opening. Timber costs more again and requires more maintenance over time.
Window Style
Casement windows are the baseline. They’re the simplest to manufacture and fit, which is why they sit at the lower end of the price range. Sash windows cost more because of the weight and balance mechanisms involved. Bay windows involve more complex framing and longer fitting times, which pushes costs higher still.
Glazing Upgrades
Standard double glazing uses two panes of glass with an air gap between them. Upgrades to that specification each carry a cost:
- Argon gas fill between the panes improves thermal performance over air
- Low-E glass coating reduces heat loss through the glass itself
- Acoustic glass adds a thicker inner pane to reduce noise transmission
- Coloured or foiled frames typically add £50 to £100 per window over white uPVC
Installation Variables
Labour typically accounts for 40% to 50% of a fitted window price. Several site-specific factors push that figure up:
- Upper-floor windows requiring scaffolding or specialist access equipment
- Non-standard opening sizes that need structural adjustment
- Disposal of old frames, which some installers exclude from their headline price
- Making good around the opening after installation
Apex quotes include VAT, fitting, and disposal with no hidden extras. If a quote looks significantly lower than the ranges in this post, check what it excludes before you sign anything.
Is It Worth Replacing 20-Year-Old Double Glazing?
Double glazing installed before 2002 is at least 50% less energy efficient than modern equivalents, according to the Glass and Glazing Federation. If your windows are showing condensation between the panes, draughts, or difficulty opening and closing, they have already degraded below the point where repair is cost-effective.
uPVC frames typically last 20 to 25 years before the seals and hardware start to fail. The glass unit seal tends to go first, which is what causes that milky or fogged appearance between the panes. Once the seal has broken, the insulating gas has escaped and the unit cannot be restored to its original performance. Resealing is not a fix. If that’s the issue you’re seeing, our guide to condensation inside double glazing covers your options in more detail.
Signs your double glazing needs replacing:
- Condensation or fogging between the panes
- Draughts around the frame when the window is closed
- Frames that have warped, discoloured, or become difficult to open
- Rising heating bills that aren’t explained by other factors
A window installed in 2002 or earlier is losing significantly more heat than a modern A+13 rated unit. Replacing like-for-like on style and material keeps the replacement cost toward the lower end of the ranges in this post. Switching from casement to sash, or from uPVC to aluminium, adds cost on top.
How Much Could You Save on Energy Bills?
Replacing single-glazed windows with A-rated double glazing saves around £140 a year on energy bills for a semi-detached home, according to the Energy Saving Trust. For a detached house, that figure rises to around £235 a year.
If you’re replacing older double glazing rather than single glazing, the savings are smaller. The performance gap between old and new units is narrower, so the annual bill reduction will be more modest. The bigger gains come from draught elimination, noise reduction, and removing the ongoing deterioration that failed seals and warped frames cause.
On a full house replacement costing £7,000 to £10,000, energy savings alone give a payback period of several decades. That’s worth being straight about. Most homeowners don’t replace windows primarily for the energy ROI. The real case is comfort, draught elimination, noise reduction, and the fact that degraded windows will only get worse.
Apex’s double glazing is A+13 rated as standard, with A++21 rated triple glazing available for properties where heat retention is the priority. See the full double glazing range for specifications.
Can You Get a Grant for Double Glazing?
Most homeowners will not qualify for a free double glazing grant in 2026. The schemes that cover glazing are means-tested and target households with lower incomes and poorly performing properties. If you’re above the income threshold, you’ll pay the full cost yourself.
Scheme | Area | Eligibility | Covers |
Warm Homes: Local Grant | England | Income under £36,000, EPC rating D to G | Up to £15,000 for energy performance upgrades including glazing |
Home Energy Scotland | Scotland | Income-based, varies by scheme | Interest-free loans and grants for energy improvements |
Nest scheme | Wales | Low income or receiving certain benefits | Energy efficiency improvements including glazing |
The Warm Homes: Local Grant launched in April 2025 with £500m of funding and runs to March 2028. Applications go through your local authority rather than a central portal, so eligibility criteria can vary slightly by area.
ECO4 has been extended to 31 December 2026 following a government consultation confirmed in January 2026. Applications through eligible energy suppliers are still open, but the scheme is winding down and supplier quotas may fill before the deadline. The Great British Insulation Scheme does not cover glazing at all, only insulation, despite the name causing some confusion.
How to Get an Accurate Double Glazing Quote
A price range tells you whether you’re budgeting in the right order of magnitude. An accurate quote needs your actual window count, sizes, and specification.
What a Proper Quote Should Include
Before you sign anything, check the quote covers:
- Supply and fitting
- VAT
- Disposal of old frames
- Making good around the openings after installation
If any of those are missing, the headline figure is not comparable to one that includes them all. A quote that looks £1,000 cheaper may not be once you add disposal and VAT back in.
What Accreditations to Look For
FENSA registration means the installer is legally obliged to register the work with your local authority on completion, confirming it meets current building regulations. That registration protects you if you sell the property. Without it, you’ll need a retrospective certificate, which costs money and causes delays.
An insurance-backed guarantee matters for the same reason. If the installer ceases trading, the guarantee transfers to the underwriter rather than becoming worthless.
Getting a Quote From Apex
Apex is FENSA registered and covers every installation with a 10-year insurance-backed guarantee through InstallSure. All fitters are directly employed. Every quote includes VAT, fitting, and disposal with no hidden extras.
Replacing double glazing is rarely an impulse decision. Most people sit on it for months, sometimes longer, once they’ve clocked the draught or noticed the condensation. Getting a realistic budget figure early makes the rest of the decision easier.
If the numbers in this post have given you a rough sense of where you stand, the next step is a specific price for your property. Apex’s instant online calculator takes under 10 seconds. If you’d rather talk it through, the team is on the contact page.
Frequently Asked Questions
How Much Should I Expect to Pay for Double Glazing?
Standard uPVC casement windows cost between £400 and £850 per window, fully installed. A typical 3-bed house with 10 windows runs £7,000 to £8,500 from a FENSA-registered installer with VAT and fitting included.
How Much Does It Cost to Double Glaze a 3-Bed House in the UK?
A 3-bed house with 8 to 12 windows costs £4,000 to £8,500 depending on installer, frame material, and what the quote includes. From a FENSA-registered installer with all costs included, expect to pay toward the upper end of that range.
Is Double Glazing Worth the Money?
The energy savings alone give a long payback period, but that’s not the main reason most people replace windows. Comfort, noise reduction, security, and the fact that degraded glazing will only deteriorate further are the stronger arguments. New double glazing can also add around 10% to property value.
Is It Cheaper to Replace All Windows at Once?
Yes. Fixed costs like scaffolding, access, and disposal are spread across the whole job, reducing the effective cost per window. It also means one installation visit rather than several.
What Is Double Glazing Cost per M2 in the UK?
Standard uPVC double glazing runs approximately £150 to £300 per m2 installed. Most installers quote per window, so use these figures for rough budgeting only.