The short answer
A new uPVC window typically costs £400–£900 supplied and fitted, so replacing all the windows in a typical 8–10 window house comes to roughly £4,000–£9,000 in 2026. Aluminium frames usually cost around 30–50% more than uPVC, and timber is typically the most expensive option. Window size and style, glass specification, energy rating and access all move the price. These are typical illustrations, not quotes — see the cost per window guide for a closer breakdown.
New windows are one of the larger home improvements most UK households take on, and the range of prices quoted — from a few hundred pounds a window to well over a thousand — can make it hard to know what is reasonable. This guide sets out realistic 2026 supply-and-fit ranges for the three main frame materials, explains what drives the differences, and flags the scenarios that push costs up so there are no surprises in a quote. All figures are typical illustrations rather than quotes, and replacement windows should be fitted by a FENSA or CERTASS registered window installer.
Double glazing costs at a glance
- uPVC window (supply & fit) £400–£900
- Aluminium window (supply & fit) £550–£1,300
- Timber window (supply & fit) £800–£1,800+
- Whole house, uPVC (8–10 windows) £4,000–£9,000
- Bay window (fitted) £900–£2,500
- Triple glazing uplift (per window) £100–£200 extra
uPVC window supply-and-fit costs
For most UK homeowners, uPVC is the default choice and the most affordable. A standard casement uPVC window typically costs £400–£900 supplied and fitted, with smaller fixed or top-hung windows at the lower end and larger or more elaborate styles toward the top. The per-window figure usually falls when you order several at once, because the installer’s setup, survey and travel costs are spread across the job. Location matters too: London and the South-East are typically 10–20% higher than the national average. For a typical three-bedroom house with 8–10 windows, the whole job in uPVC generally lands between £4,000 and £9,000. See our whole-house cost guide for figures by property size.
| Frame material | Per window (supply & fit) | Whole house (8–10 windows) |
|---|---|---|
| uPVC | £400–£900 | £4,000–£9,000 |
| Aluminium | £550–£1,300 | £5,500–£13,000 |
| Timber | £800–£1,800+ | £8,000–£18,000+ |
Aluminium and timber window costs
Aluminium frames are slimmer, stronger and increasingly popular for contemporary homes and large glazed openings; they typically cost around 30–50% more than the equivalent uPVC window. Timber frames suit period and conservation-area properties and command the highest prices, partly because of the material and partly because they need periodic repainting or staining. The performance of the glass is broadly similar across all three materials — the price difference is mainly in the frame. For a fuller comparison of looks, longevity and maintenance, see uPVC vs aluminium vs timber windows and the dedicated cost comparison.
What pushes costs up
Several factors can push a window installation above the typical ranges:
- Bay and bow windows — these need extra structural support and corner posts, so a bay window typically costs £900–£2,500 fitted. See our bay window cost guide.
- Triple glazing — the extra pane and wider frame add roughly £100–£200 per window. See double vs triple glazing for whether it is worth it.
- Acoustic or laminated glass — specified for noise or security, this adds to the glass cost. See double glazing for noise reduction.
- Difficult access — upper floors, scaffolding or awkward openings add labour and equipment cost.
- New or enlarged openings — structural work and possibly planning permission, which is far more than a like-for-like swap. See planning permission for new windows.
Energy ratings and what they add
Replacement windows must meet a minimum thermal standard under Building Regulations Part L. Most quotes will reference a Window Energy Rating (WER), which runs from A++ down to E on the BFRC scale, or a U-value, where a lower number means better insulation — good double glazing achieves around 1.2 W/m²K and triple glazing around 0.8. A higher-rated window may cost a little more but reduces heat loss. Don’t pay a large premium for the very top rating unless your home is particularly exposed; the jump from a standard A-rated window to A++ often costs more than the energy saving justifies. See window energy ratings explained.
Finance, regulations and certificates
If the upfront cost is a concern, many installers offer finance plans that spread the cost over 12–120 months. Whoever fits the windows, the work is notifiable under Building Regulations: a FENSA or CERTASS registered installer self-certifies the work and issues a certificate, which you will need when you come to sell. If you use an installer who is not registered, you must arrange building control sign-off separately. This is general information; costs vary with your specific home and the quotes you receive, and replacement windows should be fitted by a FENSA or CERTASS registered window installer.
Compare double glazing quotes
Prices vary significantly between installers for the same windows and job. Use our service to compare quotes from FENSA or CERTASS registered installers in your area.
Frequently asked questions
How much does double glazing cost for a 3-bedroom house?
A typical three-bedroom house with 8–10 windows generally costs £4,000–£9,000 in uPVC, supplied and fitted. Aluminium or timber frames, bay windows, triple glazing or upper-floor access can push this higher. These are typical illustrations, not quotes — get at least three itemised estimates for your property.
How much does one double glazed window cost?
A standard uPVC casement window typically costs £400–£900 supplied and fitted in 2026, with the per-window price usually falling when several are ordered together. Aluminium and timber cost more. Size, style, glass specification and access all affect the figure.
Is it cheaper to replace just the glass?
Yes — if the frame is sound and only the sealed unit has misted or blown, replacing just the glass typically costs £60–£200 per unit, far less than a whole new window. See our guide on whether you can replace just the glass.
Does double glazing add value to a house?
Efficient, well-fitted double glazing can support a home’s value and is often expected by buyers, particularly for its effect on the EPC rating and running costs. The exact effect varies by property and area, and it is rarely a direct pound-for-pound return on the installation cost. See is double glazing worth it.
Sources & further reading
- FENSA — guidance on replacement windows, Building Regulations compliance and finding registered installers
- Glass and Glazing Federation (GGF) — consumer guidance on window costs and specifications
- Energy Saving Trust — double glazing, energy efficiency and typical costs
- GOV.UK / Building Regulations Approved Document L — thermal standards for replacement windows
This is general information, not advice for your specific property or installation. Costs, timescales and outcomes vary with your home, the windows you choose and your chosen installer. Replacement windows should be fitted by a FENSA or CERTASS registered window installer. We are an independent information and introduction service, not an installer.