Triple Glazing Cost
2026 UK pricing for triple glazed windows: supply, installation, and whole-house costs.
Cost per Window (2026 UK Prices)
| Window Type | Triple Glazing | Double Glazing |
|---|---|---|
| Casement (1.2m × 1.2m) | £800–£1,000 | £400–£500 |
| Tilt & turn (1.5m × 1.5m) | £1,000–£1,200 | £500–£600 |
| Sash window (1.0m × 1.5m) | £1,200–£1,800 | £600–£900 |
| Patio door (2.5m × 2.1m) | £2,000–£3,000 | £1,000–£1,500 |
Whole-House Cost
- 3-bedroom semi (12 windows)
- £9,600–£14,400 (triple) vs £4,800–£7,200 (double)
- 4-bedroom detached (18 windows)
- £14,400–£21,600 (triple) vs £7,200–£10,800 (double)
- 1-bedroom flat (6 windows)
- £4,800–£7,200 (triple) vs £2,400–£3,600 (double)
What Drives the Price Beyond the Glass
Two quotes for the "same" triple glazing job can differ by thousands of pounds. Frame material is usually the biggest swing factor:
- uPVC: Cheapest frame material, widely available, and generally strong enough to take triple glazing without extra reinforcement. Good value for most retrofit projects.
- Timber: Higher cost, often required or preferred for period and listed properties, but needs careful specification to handle the extra weight of triple glazed units without warping.
- Aluminium: Slim sightlines and a modern look, but thinner aluminium profiles aren't always rated for the heavier triple glazed unit, so you may need an upgraded profile that costs more than the standard range.
- Colour and finish: Woodgrain foils, dual-colour frames (different colour inside and out), and non-standard RAL colours all add a premium over plain white.
- Access and disposal: Upper floors, scaffolding requirements, and disposal of old frames and glass are sometimes quoted separately, so check what's included before comparing prices.
Cost Breakdown
Triple glazing costs break down roughly as follows:
- Triple glazed unit (material): £300–£450/m², against £150–£250/m² for double
- Frame (uPVC, timber, or aluminium): £150–£300 per window, similar for triple and double, though triple sometimes needs a reinforced or upgraded frame profile
- Installation labour: £150–£250 per window, broadly the same for both, since fitting time doesn't change much with glazing thickness
The material cost of the glazed unit itself is what really separates triple from double, roughly double the price per square metre, because you're paying for an extra pane of glass, a second gas fill, and the low-emissivity coatings needed to make the extra pane worthwhile.
Financing and Spreading the Cost
A full triple glazing job on a 3-bedroom house runs into five figures, which is a large sum to find in one go. Most installers offer some form of payment plan, either through their own finance arrangement or a third-party lender, though the interest rate on these deals varies a lot and is worth comparing against a standard personal loan or savings before committing.
Doing the work in phases is a realistic alternative. Replacing the coldest or noisiest rooms first, typically bedrooms facing a busy road or a north-facing living room, spreads the cost over a few years while still delivering an immediate improvement where it matters most. The main downside is a small loss of bulk-order discount, since installers often price per-window jobs slightly higher than a whole-house order.
There's no dedicated government grant for triple glazing specifically. Some broader home retrofit grants and low-interest loan schemes, run at council or national level and changing periodically, do allow glazing upgrades as part of a wider package of energy efficiency work, so it's worth checking what's currently available in your area before assuming the full cost falls on you.
Getting Quotes
Get at least three quotes from FENSA or Certass-registered installers before committing. Registration matters because it means the installer can self-certify the work against Building Regulations, saving you the cost and hassle of a separate council building control sign-off.
Ask each installer for, in writing:
- U-value of the complete window, meaning frame and glazing together, not just the glazing unit on its own, which should come in at 0.8 W/m²K or better for genuine triple glazing performance
- Glass specification, including low-e coating and whether the cavities are filled with argon or krypton
- Frame material and any reinforcement needed to handle the extra weight, particularly relevant for aluminium or slim timber frames
- Warranty length, typically 10–20 years for the sealed unit itself and often shorter for the frame and hardware separately
- Whether disposal of the old windows is included in the price or charged as an extra
Be wary of quotes that seem far below the ranges above without a clear reason, sometimes it reflects a genuinely competitive local installer, but it can also mean a thinner glass specification, a weaker gas fill, or hardware that won't hold up to the extra weight over time.
How Long Does Installation Take?
From first survey to fitted windows, a whole-house triple glazing job typically takes four to eight weeks. The glazed units themselves are usually made to order once measurements are confirmed, which accounts for most of the wait, manufacturing lead time is commonly two to four weeks depending on the installer's order book and whether the frame is a standard or bespoke size.
Fitting itself is quick by comparison, usually one window per hour for a straightforward casement replacement, so a full 12-window house is often completed within one to two working days once the units arrive on site. Sash windows and bay windows take longer per opening because of the extra joinery involved, and awkward access, such as upper floors without easy scaffold points, can add time as well.
Related Guides
- Triple Glazing: Full Guide
- Is Triple Glazing Worth It?
- Triple Glazing vs Double Glazing
- Disadvantages of Triple Glazing
Sources
- Which?, "Triple Glazing: Is It Worth the Extra Cost?" (installer cost survey, 2026).
- FENSA, "Guide to Window Installation Standards" (registration and Building Regulations self-certification, 2025).
- BFRC (British Fenestration Rating Council), "Window Energy Ratings" (U-value testing methodology).
- BRE, "Domestic Window Design Guide" (frame material and reinforcement considerations, 2025).
- UK Building Regulations Part L (2021), "Conservation of fuel and power".
Last reviewed: 2026-06-27