How Much Does One Double Glazed Window Cost?
Single window prices by type and size, the minimum job charge that catches most people out, and the realistic options if you only need one window replaced.
Key takeaways
- A single uPVC casement window costs £350 to £700 supplied and fitted.
- Most installers apply a minimum job charge of £700 to £1,000, so one small window often costs more per unit than eight.
- Supply-only units start at around £150 to £350, but you still need someone to fit them.
- If three or more windows need replacing, a multi-window quote is usually better per window.
One window is the most awkward purchase in double glazing. The product itself is cheap; the visit, the van, the fitters and the paperwork are not. That is why a £180 window can arrive with a £750 invoice, and why installers prefer to quote for four windows than for one.
Single window prices by type
| Window | Typical size | Supplied and fitted |
|---|---|---|
| uPVC fixed light | 600 x 900mm | £350 – £550 |
| uPVC top-hung casement | 600 x 900mm | £380 – £600 |
| uPVC casement | 1200 x 1200mm | £450 – £900 |
| uPVC tilt and turn | 1200 x 1200mm | £550 – £1,000 |
| uPVC sash | 900 x 1500mm | £650 – £1,300 |
| uPVC bay, three section | 1800 x 1400mm | £1,200 – £2,600 |
| Aluminium casement | 1200 x 1200mm | £800 – £1,500 |
| Timber casement | 1200 x 1200mm | £900 – £2,200 |
Why one window costs more per unit
- Survey and admin. A site visit, a drawing and a contract take the same time whether you are buying one window or eleven.
- Travel and setup. Two fitters and a van for half a day cost the same to mobilise for one opening.
- Minimum order values. Fabricators often have minimum order thresholds that installers have to absorb on small jobs.
- Access equipment. If the single window is upstairs, scaffolding or a tower may cost more than the window.
- Making good and disposal. Waste removal rarely scales down; a small skip or van trip costs nearly the same.
Supply-only: is it worth it?
A supply-only uPVC casement starts at roughly £150 to £350, and a made-to-measure sealed unit alone can be £60 to £150. If you are competent with a tape measure, understand trickle ventilation and can fit and seal a frame square, supply-only can save 40% to 60%.
The catch is compliance and guarantee. Replacement windows must meet building regulations for thermal performance and safety glazing, and the FENSA or CERTASS certificate comes from the installer. A self-fitted window needs a building control application, which costs more than the saving on a single unit. There is also no installer guarantee if your own fitting leaks.
Better ways to buy one window
- Bundle it. If three or more windows are near the end of their life, quote them together and the per-window price drops sharply.
- Ask about a repair first. A misted unit often only needs a new glass unit, at £80 to £200 fitted, not a whole window.
- Go local. Small independent installers are more likely to take a one-window job at a sensible price than a national firm with fixed minimums.
- Consider a matching second-hand or ex-display frame only if the size is exact, and never for a bedroom or a door.
The bottom line
Expect £350 to £900 for one standard uPVC window supplied and fitted, and do not be surprised by a £700 to £1,000 minimum job charge. If the glass is misted but the frame is sound, price a replacement unit before you price a replacement window.
Frequently asked questions
Yes. Any installer can replace a single window, though many apply a minimum charge of £700 to £1,000. Small local firms are usually more flexible on one-off jobs.
A replacement sealed glass unit costs roughly £80 to £200 fitted, depending on size and glass type. That is far cheaper than a new window if the frame is still sound.
Supply-only can cut 40% to 60% off the price, but you still need building control sign-off, correct safety glazing and a weathertight installation. On a single window the saving is usually eroded by compliance costs.
Likely a minimum job charge, upstairs access needing equipment, or a premium frame and glass specification. Ask for the quote itemised so you can see what is driving it.
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