Triple Glazed Windows Cost in the UK: Prices in 2026
TL;DR
Triple glazing costs about £1,200 per window fitted in the UK, with uPVC from £800 to £2,000. An 8-window semi costs about £9,600.
Table of Contents
Triple glazed windows cost: the short version
Triple glazing costs about £1,200 per window fitted in the UK. That is the Checkatrade guide figure, and it is also the number you get when you multiply the 8 windows of a typical semi-detached house by £1,200: £9,600, which is Checkatrade whole-house figure for a semi. uPVC windows start lower, at £800 to £2,000 each, and timber windows start higher, at £1,200 to £2,500 each.
Triple glazing adds a third pane and a second gas-filled gap to the double glazed unit. The extra pane cuts heat loss, and the inside of the glass stays warmer, so condensation drops. It costs 20 to 40% more than the same window in double glazing, and it weighs more, so the frame and hinges need to be up to the job.
Figure 1: A modern house with floor-to-ceiling glass. Large panes like these are where triple glazing shows its strength: the extra pane cuts heat loss through big glazed areas.
Triple glazing cost per window
| Window style | Typical fitted cost | Notes |
|---|---|---|
| uPVC casement | £550 to £1,200 | Cheapest triple glazed option, per window by size. |
| Triple glazed sash | £1,100 to £2,500 | Period homes. Heavier, dearer to make and fit. |
| Triple glazed bay | £2,000 to £4,500 | Three or more panes in one bay frame. |
BestBuilders puts uPVC casement triple glazing at £550 to £1,200, which matches the table above.
Cost by frame material
| Frame material | Typical cost per window | Notes |
|---|---|---|
| uPVC | £800 to £2,000 | Lowest cost, lowest upkeep, widest choice. |
| Aluminium | £1,000 to £2,200 | Slimmer frames, more glass, strong and light. |
| Timber | £1,200 to £2,500 | Best look for period homes, needs paint or stain. |
Whole-house cost
The price for a full house depends on the count, not the average alone. Checkatrade puts a 5-window terrace at about £6,000, an 8-window semi at £9,600 and a 12-window detached house at £14,400, all at the £1,200 average. BestBuilders puts 8 windows at £4,800 to £9,500, which reflects cheaper uPVC casements at the bottom and timber or sash at the top.
Worked example: an 8-window semi
Take a semi-detached house with 8 windows: 3 bedrooms, a bathroom, a kitchen, a lounge and a landing window. At the Checkatrade average of £1,200 per window, the bill is 8 times £1,200, which is £9,600. That is Checkatrade whole-house figure for an 8-window semi, so the two routes agree. If the same house uses uPVC casements at £700 each, inside the published £550 to £1,200 range, the bill is £5,600. If it uses timber sash at £2,000 each, inside the published £1,100 to £2,500 range, the bill is £16,000. The window count and the frame material decide the total, not the average.
Triple glazing vs double glazing: is it worth it?
Triple glazing costs 20 to 40% more than the same window in double glazing. BestBuilders puts the premium at 20 to 40%, GreenMatch at 30 to 40%. On a £9,600 job, that is an extra £1,920 to £3,840. Building regulations set a maximum whole-window U-value of 1.4 W/m2K for new windows in England and Wales, and both double and triple glazing pass that. Triple glazing pays best in cold exposed homes, in homes near busy roads where the extra pane cuts noise, and in rooms with very large glass. In a small warm flat, good double glazing is often the better buy.
Sources: Checkatrade triple glazed windows cost guide, updated May 2026 and October 2026 (average £1,200 per window; uPVC £800 to £2,000; aluminium £1,000 to £2,200; timber £1,200 to £2,500; 8-window semi £9,600; 12-window detached £14,400); BestBuilders triple glazing cost guide, updated 15 October 2026 (uPVC casement £550 to £1,200; sash £1,100 to £2,500; bay £2,000 to £4,500; premium over double 20 to 40%); GreenMatch triple glazing cost guide 2026 (premium 30 to 40% over double); Checkatrade replacement window cost guide 2026 (Part L U-value 1.4 W/m2K). Prices checked 14 November 2026.
Frequently asked questions
How much does triple glazing cost per window?
About £1,200 fitted on average in the UK. uPVC casement windows run £550 to £1,200, aluminium £1,000 to £2,200 and timber £1,200 to £2,500.
How much does it cost to triple glaze a whole house?
About £6,000 for a 5-window terrace, £9,600 for an 8-window semi and £14,400 for a 12-window detached house at the £1,200 average. Cheaper uPVC casements bring those totals down.
Is triple glazing worth the extra cost?
It costs 20 to 40% more than double glazing. The extra pane cuts heat loss and keeps the inner pane warmer, which also cuts condensation. It pays best in cold exposed homes, near busy roads, and in rooms with very large glass.
Does triple glazing stop condensation?
It cuts it. The inner pane stays warmer, so water is less likely to form on it. It does not fix condensation caused by poor ventilation or damp walls.
Do I need planning permission for triple glazing?
No, not for a like-for-like replacement in most homes. Listed buildings and homes in conservation areas need consent, and the new windows should match the original style.
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