Short answer: in 2026 most published UK guides put a standard double-glazed UPVC casement window at roughly £350 to £1,250 fitted, with aluminium typically £475 to £1,100 or more, and a whole three-bedroom house anywhere from about £3,750 to £15,000 depending on material, window count and who you ask. The ranges are wide because the sources measure different things, so this guide sets them side by side, explains where they disagree, and shows what actually moves a quote. All figures below are market guides from the named sources, not Inspired Glazing prices.
New window prices at a glance (2026)
| Window or job | Typical 2026 price, fitted | Source |
|---|---|---|
| UPVC casement window | £350 to £550 | ExpertSure |
| UPVC casement window | £500 to £1,250 | Checkatrade |
| UPVC sash window | £700 to £1,100 | ExpertSure |
| Aluminium casement window | £600 to £850 | ExpertSure |
| Aluminium casement window | Average £475 | Checkatrade |
| Aluminium casement window | £750 to £2,250 (fitting may not be included) | The Eco Experts |
| Two-bed terrace, aluminium (6 to 8 windows) | £3,000 to £4,000 | ExpertSure |
| Three-bed semi (8 to 12 windows) | About £3,750 UPVC; £4,700 to £5,600 aluminium | ExpertSure |
| Three-bed semi (8 to 12 windows) | £8,000 to £15,000 | Checkatrade |
| Four-bed detached (10 to 15 windows) | £5,500 to £7,000 UPVC; £7,000 to £9,000 aluminium | ExpertSure |
| Inspired Glazing aluminium windows | From £400 per window | Our price; lead times from 10 days, 10-year guarantee |
Get a free, fixed-price quote
Made in our own Fifield workshop and fitted by our own team. Aluminium windows from £400, lead times from 10 days and a 10-year guarantee. Tell us what you need and we’ll book a free survey.
We make aluminium windows in our own workshop at Fifield, near Windsor, and install UPVC and aluminium double glazing across Berkshire, Buckinghamshire, Surrey, west Kent and north West Sussex. For a deeper look at aluminium specifically, see our aluminium windows cost guide.
Price per window: what the 2026 guides say
These are the most recent published figures we could find, checked in October 2026. Unless noted, they are for supply and installation of a standard casement window.
UPVC double glazing
- ExpertSure (verified October 2026, including VAT): £350 to £550 for a UPVC casement, £700 to £1,100 for a UPVC sash.
- Checkatrade (May 2026): a standard UPVC casement “starts at around £500”, with casements generally £500 to £1,250.
- FMB HomePicks (October 2026): around £500 per UPVC window.
- MyBuilder (August 2026): £160 to £250 for a basic 600 × 900 mm UPVC casement. This looks closer to a materials figure, and the same page labels its whole-house numbers as material costs.
Aluminium double glazing
- Checkatrade: an average of £475 per aluminium window.
- ExpertSure: £600 to £850 for an aluminium casement.
- The Eco Experts (tables dated February 2026, data credited to a national installer): £750 to £2,250 for an aluminium casement (the page doesn’t make clear whether fitting is included). It says aluminium generally runs about 25% above UPVC.
Where the sources disagree: Checkatrade’s average aluminium figure (£475) is actually lower than its own UPVC starting point (£500), while The Eco Experts puts aluminium at up to several times that. The likely reasons are different window sizes, whether thermally broken profiles and colours are assumed, and whether the data comes from tradesperson surveys or one national brand’s list prices. Treat any single number with caution.
Inspired Glazing’s own starting price
Our aluminium windows start from £400. Lead times start from 10 days, because we fabricate in-house, and we give a 10-year guarantee. Our UPVC windows use the Selecta Advance 70 system. Your actual price depends on size, opening type, colour and glass, and we confirm it after a free survey.
Whole-house double glazing costs by house size
Whole-house estimates vary even more than per-window ones, because the number of windows assumed for each house type differs between sources.
- Two-bed terrace (6 to 8 windows): ExpertSure quotes £3,000 to £4,000 for aluminium. Checkatrade gives no figure, only that two-bed homes “may cost less”.
- Three-bed semi (8 to 12 windows): ExpertSure, quoting MyJobQuote data, gives about £3,750 for UPVC and £4,700 to £5,600 for aluminium. Checkatrade gives £8,000 to £15,000 for 8 to 12 windows. MyBuilder suggests £4,000 to £7,000 for UPVC and £10,000 to £15,000 for a premium specification.
- Four-bed detached (10 to 15 windows): ExpertSure gives £5,500 to £7,000 for UPVC and £7,000 to £9,000 for aluminium.
- By property type: The Eco Experts works on roughly £1,000 per UPVC window. That gives £8,000 for an eight-window bungalow, £16,000 for a 16-window semi and £20,000 for a 20-window detached house, plus about 25% for aluminium.
Where the sources disagree: for the same three-bed semi, the cheapest published UPVC estimate (around £3,750) is less than half Checkatrade’s lower bound (£8,000). In practice, budgets near the lower figures usually assume small white UPVC casements and few extras. Bay windows, coloured frames, larger openings and access needs push homes towards the higher figures.
If you are comparing materials more broadly, our pages on UPVC windows and energy-rated windows explain the performance side.
What pushes a double glazing quote up or down
- Window style. Checkatrade puts sash windows at £700 to £1,500 and bay windows at £1,100 to £4,000, against £500 to £1,250 for casements. A bay is several frames joined together, so it costs more to make and fit.
- Size and number. Big panes need thicker or toughened glass, and replacing every window in one visit usually costs less per window than doing them in stages.
- Frame colour. The Eco Experts says colour finishes add 10 to 20%. Grey and black are popular, and our grey and black windows page covers the options.
- Glass specification. Acoustic, solar-control, obscure or safety glass adds cost, as does moving up to triple glazing (see double vs triple glazing).
- Access. Checkatrade estimates scaffolding at around £1,000 a week where upstairs windows can’t be reached safely from ladders or towers.
- Making good. Old frames sometimes hide rotten sub-frames, damaged lintels or crumbling reveals that need repair before the new window goes in.
VAT on double glazing: it is 20%
Double glazing is charged at the standard 20% VAT rate. HMRC’s notice on energy-saving materials says that “secondary or double glazing, low-emissivity glass” are standard-rated, so they do not qualify for the 0% relief that applies to items like insulation and heat pumps (GOV.UK, VAT Notice 708/6). When you compare quotes, check whether each one includes VAT. A price that looks £1,000 cheaper may simply be shown before VAT.
Grants for double glazing are limited
There is no government grant aimed only at double glazing. FMB HomePicks (October 2026) lists these as the main routes:
- Warm Homes: Local Grant (England, 2025 to 2028): can include double or triple glazing, but only for homes rated EPC D to G, in a participating council area, and usually with household income under £36,000 or qualifying benefits.
- ECO4: runs to 31 December 2026, funds windows only as part of a wider package such as wall or loft insulation, and is aimed at households on qualifying benefits.
The Eco Experts says grants “can help with up to 100% of the cost”, but only if you meet the eligibility rules. Most owner-occupiers in Berkshire, Buckinghamshire and Surrey will be paying for replacement windows themselves, so it is worth weighing up savings and comfort instead.
How much will double glazing save?
Again the figures differ. The Energy Saving Trust (May 2026) estimates that fitting A-rated double glazing in a fully single-glazed semi-detached home saves about £85 a year in Great Britain. Some cost guides quote £140 a year, which is the Energy Saving Trust’s Northern Ireland figure. If you are replacing old double glazing rather than single glazing, the saving will be smaller. Replacement is usually about comfort, condensation, security and appearance as much as bills.
How to get an accurate double glazing price
- Get at least two or three quotes for the same specification: frame system, glass, colour, hardware and whether VAT is included.
- Ask what the guarantee covers and for how long. Ours is 10 years.
- Check the installer will give you a Building Regulations compliance certificate. Replacement windows have needed one since April 2002 (Planning Portal).
- If you live in a conservation area or a listed building, read our planning permission for replacement windows guide first.
Get a fixed quote for your home
Online ranges are only a starting point. We will measure every opening, talk you through UPVC and aluminium options side by side, and give you a written price with no obligation. Call 01753 965 005 or request your free quote, and we will arrange a survey at a time that suits you.
Frequently asked questions
How much does one double glazed window cost in 2026?
Published 2026 guides put a standard fitted UPVC casement at roughly £350 to £1,250 and aluminium at about £475 to £1,100, with some sources higher. Size, style, colour and glass make the biggest difference. Inspired Glazing's aluminium windows start from £400, and we confirm the exact price after a free survey of your openings.
Is VAT charged on double glazing?
Yes. Double glazing is standard-rated at 20% VAT. HMRC's VAT Notice 708/6 lists secondary and double glazing and low-emissivity glass as standard-rated, so the 0% energy-saving materials relief does not apply. Always check whether a quote shows prices before or after VAT, as this can make one quote look much cheaper than another.
How much does it cost to double glaze a 3 bed house?
Estimates range widely. ExpertSure quotes around £3,750 for UPVC and £4,700 to £5,600 for aluminium, while Checkatrade gives £8,000 to £15,000 for 8 to 12 windows. Bays, coloured frames, large openings and scaffolding push the price towards the higher figures. A survey gives you a reliable number for your specific house.
Can I get a grant for double glazing?
Only in limited cases. There is no grant for double glazing on its own. The Warm Homes: Local Grant can include glazing for lower-income households in homes rated EPC D to G, and ECO4, which runs to December 2026, funds windows only alongside wider insulation work. Most homeowners pay for replacement windows themselves.
Is aluminium double glazing more expensive than UPVC?
Usually, yes. The Eco Experts says aluminium typically costs about 25% more than UPVC, and most guides show a premium of a few hundred pounds per window. Aluminium gives slimmer frames, more colour choice and a long life. Our aluminium windows start from £400, and we can quote UPVC alongside so you can compare.