Window Replacement Cost: What You'll Pay Per Window and Whole House

Two ways to think about window replacement cost

Most homeowners come at this question from one of two directions. Either a single window has failed and needs pricing on its own, or the whole house needs doing at once and the question is really about a project total. Both are valid ways to budget, but they produce very different looking numbers, so it helps to be clear which one you are actually asking about before you compare quotes.

Per-window pricing is driven mainly by size, style and glazing spec. Whole house pricing is driven by those same things multiplied across every opening, plus some economies of scale on labour, scaffolding where needed, and site set-up that a single window replacement does not benefit from.

Cost per window by style

As a rough guide only, here is where different window styles typically land supplied and fitted in uPVC. Aluminium and timber alternatives sit above these figures, and every range depends on glass spec, colour and access.

• Small casement window: roughly £350 to £600
• Standard casement window: roughly £500 to £900
• Tilt and turn window: roughly £550 to £950
• Flush sash casement window: roughly £600 to £1,050
• Bay window (three panels): roughly £1,800 to £3,800
• Sash window, uPVC vertical slider: roughly £700 to £1,300

Cost per window by size

Size has a real effect within any given style. A small bathroom or utility window costs noticeably less than a large lounge window of the same style, simply because there is more glass and frame material involved, and larger openings sometimes need reinforced frames to stay rigid. When comparing quotes, always check the actual dimensions being priced rather than assuming a like-for-like style comparison, since a generously sized casement can cost more than a smaller bay.

Whole house replacement by property type

Pricing a whole house is really pricing every opening and adding them together, but most installers can offer a modest saving over doing each window separately because of shared scaffolding, a single site visit and one delivery.

• Two-bed terrace, typically 6 to 8 windows: roughly £4,000 to £7,000
• Three-bed semi, typically 8 to 10 windows: roughly £5,500 to £9,500
• Four-bed detached, typically 10 to 14 windows: roughly £8,000 to £14,000 or more
• Bungalow, typically 8 to 10 windows: roughly £5,000 to £8,500

What a fitted price should actually include

A properly itemised fitted price covers more than just the window unit itself. It should include removal and disposal of the old frames, making good to internal reveals and external render or brickwork, all fixings and insulation around the new frame, trickle vents where required by regulations, and a final clean of the glass and surrounding area. If a quote looks unusually cheap, it is worth checking whether disposal and making good are actually included, since some cheaper quotes leave those as extras.

What moves the price up or down

Glass specification is one of the biggest variables. Standard double glazing is the baseline, while acoustic glass, triple glazing or solar control coatings all add cost per window. Frame material matters too, with aluminium and timber alternatives sitting above standard uPVC. Access is another factor that is easy to overlook, since upstairs windows on a property without easy scaffold access, or windows above a conservatory roof, can add labour time that a straightforward ground floor window does not need.

Non-standard sizes and shapes, such as an arched top or an unusually wide opening, also push cost above a stock-sized window because more of the frame has to be made to order rather than cut from standard lengths.

Should you replace windows all at once or gradually?

Doing the whole house in one visit is usually more cost-effective per window than spreading the work over several years, because you only pay for one site set-up, one round of scaffolding if needed, and one delivery. It also means every window matches in colour and style from day one. The trade-off is a larger single outlay, so some households choose to prioritise the worst-performing windows first and do the rest in a second phase, which is a perfectly reasonable approach if budget is the limiting factor.

Getting an accurate figure for your home

Every property is different, and the only way to know what your windows will actually cost, whether that is one window or the whole house, is a free, no-obligation survey. We measure every opening, talk through style and glazing options, and give you a fixed written quote broken down window by window, so you can see exactly what you are paying for and where.

Common questions

Is it cheaper per window to replace the whole house at once?

Usually yes, because scaffolding, site set-up and delivery are shared across all the windows rather than repeated for each one, so the per-window cost tends to be a little lower than doing them individually over time.

Does window style make a big difference to cost?

It can. A bay window with three panels and often a hip or gable roof detail costs considerably more than a single standard casement of similar total glass area, simply because there is more structure involved.

Are upstairs windows more expensive to fit than downstairs ones?

Sometimes, particularly if scaffolding or a tower is needed for safe access, which adds labour cost that a ground floor window with easy access does not carry.

What is usually included in a fitted window price?

A properly itemised price includes the window unit, removal and disposal of the old frame, making good to reveals, fixings and insulation, trickle vents where needed, and a final clean, though it is always worth checking this against any quote you receive.

Can I replace just one window rather than the whole house?

Yes, single window replacement is common, for example after a failed seal or accidental damage, and is priced on its own merits without needing to commit to the rest of the house.