How much does double glazing cost in the UK?
Window quotes are usually built up per opening, then adjusted for frame material, glass specification, access and how the old frames come out. As an indicative planning range, a uPVC casement window commonly falls somewhere around £450–£900 supplied and fitted, with a whole-house replacement more often in the £4,000–£10,000 region.
Two window quotes for the same house can differ by thousands without either being unreasonable. Frame material, glass unit specification, opener count, trickle vents, scaffolding and who makes good the plaster and render all move the figure.
Replacement windows in England and Wales are regulated work. The installer should either be registered with a competent person scheme such as FENSA or Certass, or the work should be notified to Building Control. Ask which applies and who issues your certificate.
All figures here are indicative estimates for planning only. QuoteCheck does not hold a live UK pricing feed, and real prices vary with location, product range, survey findings and how each firm prices labour.
Indicative UK cost ranges
QuoteCheck does not hold a live UK pricing feed. The figures below are indicative planning ranges, assembled from commonly published UK ranges and typical job structures, and they are deliberately wide. Treat them as a starting point for questions, not as a valuation. Real prices depend on specification, access, ground conditions, region, season and how each firm prices its own labour and overheads.
| Item | Unit | Indicative range |
|---|---|---|
| uPVC casement windowStandard sizes; more openers cost more than fixed panes. | per window, fitted | £450 – £900 |
| uPVC sash windowSliding sash mechanisms carry a premium. | per window, fitted | £800 – £1,600 |
| Aluminium windowSlimmer sightlines, higher frame cost. | per window, fitted | £800 – £1,800 |
| Timber windowHardwood and conservation styles at the upper end. | per window, fitted | £1,000 – £2,500 |
| Bay windowStructural support above the bay may be needed. | per bay, fitted | £1,500 – £3,500 |
| uPVC front or back doorComposite doors usually above uPVC. | per door, fitted | £800 – £1,800 |
| Whole house, typical 3-bedDepends on opening count, material and glass spec. | per project | £4,000 – £10,000 |
| Scaffolding or access towerUpper floors, awkward frontage or a conservatory below. | per job | £300 – £1,200 |
What moves the price
- Number and size of openings
- Windows are priced per opening, so count them and note which are fixed.
- Frame material
- uPVC, aluminium and timber sit at very different price points for the same opening.
- Glass specification
- Energy rating, toughened or laminated safety glass, acoustic units, obscure glass and Georgian bars all change the unit price.
- Removal and disposal
- Taking out old timber or steel frames is slower than removing uPVC, and old units are charged to tip.
- Access
- First-floor and above may need towers or scaffolding, priced separately.
- Making good
- Internal plaster reveals, external render or brickwork, sills and trims — often the difference between two quotes.
- Property type
- Listed buildings and conservation areas restrict what can be fitted and raise the cost.
Worked example — 9 uPVC windows and one door (illustrative only)
- 7 casement windows
- £4,200
- 2 first-floor windows with access
- £1,500
- uPVC back door
- £1,100
- Removal and disposal of old frames
- £450
- Internal reveals and external trims
- £600
- Certification and registration
- £120
- Indicative total before VAT
- £7,970
Fictional arithmetic to show how a window total is built up. Your own quote may differ for entirely legitimate reasons.
What your quote should show
- Every opening listed separately with its size and style
- Frame material and product range named
- Glass specification, including toughened or laminated where required
- Opener count per window and any trickle vents
- Removal and disposal of the old frames
- Access equipment where needed
- Making good internally and externally
- FENSA, Certass or Building Control certification and who provides it
- Guarantee length on frames, glass units and installation
- VAT treatment and deposit terms
Before you agree to the quote
- What is usually excluded
- Internal decoration after plaster reveals are made good, curtain and blind refitting, replacing rotten sub-sills or lintels found on removal, and alarm sensors on old frames.
- VAT
- Most window installers are VAT registered and add 20%. Check whether each quote is quoted inclusive or exclusive before ranking them.
- Deposits and payment
- A deposit is normal because units are made to measure, but paying the majority up front is not. Ask whether your deposit is protected under the installer's scheme.
- Discount pressure
- A price that only stands 'if you sign today' is a sales tactic, not a survey-based figure. A genuine quote should hold for a stated period, commonly 30 days.
- Comparing quotes
- Line the quotes up opening by opening, with the same frame material and glass spec, then compare access, making good and certification separately.
- Questions to ask before accepting
- Who carries out the final survey? What happens if sizes differ from the survey? Who makes good inside and out? What exactly does the guarantee cover, and is it insurance backed?
Frequently asked questions
How much does double glazing cost for a whole house in the UK?
Indicatively £4,000–£10,000 for a typical three-bedroom house in uPVC, depending on how many openings there are, the glass specification and access. Aluminium and timber usually sit well above that.
How much is one double glazed window?
Indicatively £450–£900 supplied and fitted for a standard uPVC casement, higher for sash, aluminium, timber and bay windows.
Why do window quotes vary so much?
Because the opening count, frame range, glass specification, access, disposal and making good differ. A cheaper quote often excludes reveals, trims or certification that another includes.
Do replacement windows need building regulations approval?
Yes. The work is either notified by an installer registered with a scheme such as FENSA or Certass, or through Building Control. Ask who is certifying it and when you receive the certificate.
Is a big discount for signing today a good sign?
Usually not. A price based on a real survey should stand for a stated period. Treat time-limited pressure as a reason to take the quote away and check it.
Can QuoteCheck tell me if my window quote is fair?
QuoteCheck reviews the quote and details you provide and returns an independent second opinion for £9.99 — an estimated reasonable range, questions to ask and a suggested target price. It is an estimate, not a guarantee.
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