Windows · by style
Bay windows
A bay window projects out from the wall in three angled panels, bringing in light from three sides and adding a little floor space. Replacing one means making the window up as a complete assembly, with posts and couplers that carry the weight of the bay roof above.
Is it right for your home?
Suits
- Victorian, Edwardian and 1930s houses with existing bays
- Living rooms and bedrooms at the front of the house
Good points
- More light and a sense of space
- Usually replaced like for like with no planning needed
Watch out for
- Dearer than flat windows of the same width
- The bay roof above may need work at the same time
What bay windows cost
Bay windows typically cost £2,000 (one three-panel uPVC bay window), with most jobs between £1,200 and £2,800. That includes VAT at 20%. Fitting takes 1 day on site.
What you would actually pay
Typical one three-panel uPVC bay window · UK- Typical installed cost Bay windows, supplied and fitted
- £1,667
- VAT at 20% Standard rate
- £333
- Net cost to you
- £2,000
If you borrowed £2,000.00 over 36 months at 0.0%, it would cost £55.56 a month – £2,000.00 in total, of which £0.00 is interest. The last payment would be £55.40.
Illustration only – not a quote, not an offer of credit, and not financial advice. Rates depend on your circumstances and creditworthiness.
Where the money goes
| Element | Typical range |
|---|---|
| Bay window Three made-to-measure uPVC panels with corner posts and double glazing. | £960 – £2,200 |
| Fitting Supporting the bay roof, removing the old frames and fitting the new assembly. | £200 – £410 |
| Making good Making good the plaster, board and sill inside the bay. | £50 – £190 |
Guide prices including VAT. Your actual cost depends on your home, access and specification.
What moves the price
- Load-bearing posts
Many bays carry the weight of the roof or the wall above through the frame. The posts have to be rated for it, which adds to the price and is not something to cut.
- Bay or bow
A bow window curves in four or five panels and costs more than a three-panel bay.
- The roof above
If the bay roof leaks, fix it while the window is out. It is cheaper than going back later.
What should be in a quote
If a quote is missing any of these, ask why before you compare it with another.
- How the bay roof will be supported while the old frame is out
- Whether the corner posts are load bearing, and their rating
- The style of each panel and which ones open
- The board or sill inside the bay
- FENSA or CERTASS registration
- Whether any repair to the bay roof is included or priced separately
Prices by region
Labour is most of the difference. Typical price (one three-panel uPVC bay window), including VAT.
| Region | Typical | vs UK average |
|---|---|---|
| London | £2,500 | +25% |
| South East | £2,300 | +17% |
| South West | £2,200 | +10% |
| East of England | £2,100 | +6% |
| West Midlands | £2,100 | +4% |
| Scotland | £2,000 | +2% |
| East Midlands | £2,000 | UK average |
| Yorkshire and the Humber | £2,000 | UK average |
| North West | £1,900 | −2% |
| North East | £1,900 | −5% |
| Wales | £1,900 | −6% |
| Northern Ireland | £1,700 | −12% |
Common questions
Is a bay window structural?
Often, yes. In many older houses the bay frame supports the roof or wall above, so the installer must prop it and fit posts rated to carry the load.
Should I fix the bay roof at the same time?
If it leaks or the lead is tired, yes. The window installer can usually arrange it while the frame is out.
Get quotes for your home
A guide price only takes you so far. Local firms can price the work on your own home, and comparing a few quotes is the quickest way to see what is reasonable.
Compare free quotes