Triple Glazing vs Double Glazing: Cost Comparison
Triple glazing costs 40% to 60% more than double glazing and is genuinely better in noise and extreme cold, but for most UK homes the payback is long. Here is the honest comparison.
Key takeaways
- Triple glazing typically costs £150 to £400 more per window than double glazing.
- Frame weight and depth can add cost: some uPVC profiles and most existing openings need checking.
- Triple glazing wins clearly on acoustic insulation and cold-climate performance.
- The energy saving alone rarely repays the premium within 20 years for a typical UK home.
Triple glazing is the most oversold upgrade in the UK window market. It is a genuinely better product, but the sales pitch usually claims a heating bill reduction that the physics does not support in a temperate climate. Below is what the extra money actually buys.
Cost comparison per window
| Window type | Double glazed | Triple glazed |
|---|---|---|
| uPVC casement, 600 x 900mm | £350 – £700 | £500 – £950 |
| uPVC casement, 1200 x 1200mm | £450 – £900 | £650 – £1,250 |
| uPVC tilt and turn, 1200 x 1200mm | £550 – £1,000 | £780 – £1,400 |
| uPVC bay, three section | £1,200 – £2,600 | £1,700 – £3,600 |
| Aluminium casement, 1200 x 1200mm | £800 – £1,500 | £1,100 – £2,100 |
Across a typical three-bedroom house, that translates to roughly £1,500 to £3,000 extra for triple glazing over double. It is not a small upgrade, and it is the first line most installers will try to sell you.
The performance difference
| Measure | Good double glazing | Triple glazing |
|---|---|---|
| U-value | 1.2 – 1.4 W/m²K | 0.8 – 1.0 W/m²K |
| Energy rating | A to A+ | A+ to A++ |
| Acoustic reduction | 30 – 34 dB | 35 – 40 dB |
| Weight | Standard | 25% – 40% heavier |
| Typical extra cost | — | +40% to +60% |
Why the payback is usually long
Windows are a minority of a home’s heat loss, and the difference between good double glazing and triple glazing is a small fraction of that minority. For a typical three-bedroom house, the realistic annual saving over A-rated double glazing is often £20 to £60, which against a £2,000 premium is a payback measured in decades. Replacing single glazing with double is transformative; upgrading good double to triple is marginal.
Practical considerations before you order
- Reveal depth. Triple glazed units are 40mm to 52mm thick against 24mm to 28mm, so the frame is deeper and some openings cannot take them without alteration.
- Weight. Heavier sashes need stronger hinges and better fixings. Cheap hardware on heavy units fails early.
- Opening lights. Large triple glazed casements can sag; tilt and turn handles the weight better.
- Bays and conservatories. Extra weight on bay roofs and conservatory frames needs checking by the installer.
- Planning and conservation. In conservation areas and listed buildings, thicker frames may be refused where slim double glazing would be allowed.
Our verdict
- Replace single glazing on a budget: good A-rated double glazing.
- Noisy road, railway or airport: triple glazing, or acoustic laminated double if the frame depth is tight.
- Cold, exposed, rural location: triple glazing is worth considering.
- Typical suburban home, windows already double glazed: not worth the premium.
The bottom line
Triple glazing costs roughly 40% to 60% more, or £150 to £400 extra per window. Buy it for quiet and comfort, not for a heating-bill payback that probably will not arrive. If noise is your main concern, ask about acoustic laminated double glazing first, because it often costs less for a similar result.
Frequently asked questions
For noise reduction and very exposed locations, often yes. For a typical suburban home upgrading from good double glazing, the energy saving rarely justifies the 40% to 60% premium.
Around £150 to £400 per window, or £1,500 to £3,000 more across a typical three-bedroom house.
Yes, noticeably, especially with asymmetric glass thicknesses. If noise is the priority, acoustic laminated double glazing can be a cheaper alternative with a similar effect.
Usually not. The units are 40mm to 52mm thick, so the frame must be designed for them. Retrofitting triple units into standard double glazed frames is rarely possible.
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