Windows · other glazing
Triple glazing
Triple glazing has three panes of glass and two sealed gaps instead of two panes and one. It keeps more heat in and cuts more noise, but the step up from good modern double glazing is smaller than the step from single glazing, so it pays back slowly in most British homes.
Is it right for your home?
Suits
- Homes on busy roads or under flight paths
- Cold, exposed or north-facing rooms
- Deep retrofits aiming for very low heating bills
Good points
- Lower heat loss than double glazing
- Quieter rooms
- Less condensation on the inner pane
Watch out for
- Costs more than double glazing for a modest extra saving
- Heavier units need stronger frames and hinges
- Lets in slightly less light and solar warmth
What triple glazing costs
Triple glazing typically costs £700 (one triple glazed uPVC casement window), with most jobs between £500 and £950. That includes VAT at 20%. Fitting takes 2–4 hours on site.
What you would actually pay
Typical one triple glazed uPVC casement window · UK- Typical installed cost Triple glazing, supplied and fitted
- £583
- VAT at 20% Standard rate
- £117
- Net cost to you
- £700
If you borrowed £700.00 over 36 months at 0.0%, it would cost £19.44 a month – £700.00 in total, of which £0.00 is interest. The last payment would be £19.60.
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 |
|---|---|
| Window A made-to-measure uPVC casement with a triple glazed sealed unit. | £410 – £780 |
| Fitting Removing the old window and fitting the new, heavier frame. | £100 – £170 |
Guide prices including VAT. Your actual cost depends on your home, access and specification.
What moves the price
- Frame
The frame has to be deep enough for the thicker unit. Most current uPVC profiles are; older or slimmer ones may not be.
- Size and weight
Three panes make large sashes heavy, which needs stronger hinges and can limit the sizes available.
- Glass specification
Low-emissivity coatings and argon fill on both cavities give the best result. Ask what is included.
What should be in a quote
If a quote is missing any of these, ask why before you compare it with another.
- The size of each window and which way it opens
- The frame profile or brand, and its colour inside and out
- The glass: its energy rating or U-value, and toughened glass where it is needed
- Removal of the old windows and making good inside
- FENSA or CERTASS registration, so the work is certified
- The guarantee on frames, glass and hardware
Prices by region
Labour is most of the difference. Typical price (one triple glazed uPVC casement window), including VAT.
| Region | Typical | vs UK average |
|---|---|---|
| London | £870 | +25% |
| South East | £810 | +17% |
| South West | £770 | +10% |
| East of England | £740 | +6% |
| West Midlands | £720 | +4% |
| Scotland | £710 | +2% |
| East Midlands | £700 | UK average |
| Yorkshire and the Humber | £700 | UK average |
| North West | £680 | −2% |
| North East | £660 | −5% |
| Wales | £650 | −6% |
| Northern Ireland | £610 | −12% |
Common questions
Is triple glazing worth it?
For most homes replacing old windows, A-rated double glazing gives nearly all of the saving for less money. Triple glazing earns its place where noise or cold is the main problem.
Can I add a third pane to my double glazing?
Not to the sealed unit. Secondary glazing, fitted inside the existing window, is the way to add a layer.
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