Triple glazing FAQ

A sealed glass unit with three panes and two gas-filled cavities. With two low-e coatings it loses about half the heat of good double glazing through the glass.

When you are replacing single or failing double glazing, or have cold, noisy or north-facing rooms, yes. If your double glazing is modern and sound, the bill savings are small and the case rests on comfort. Read our full guide.

At the centre of the glass, about Ug 0.6 against 1.1 W/m²K. Across a whole window, typically about 0.8 against 1.2 to 1.4.

Slightly less than double glazing. In most rooms the difference is hard to notice.

It lets in less solar heat than double glazing, so it tends to keep rooms cooler. Large south or west windows may still need shading.

The glass is about 50% heavier than double, but the frames, hinges and fixings are designed for it. The wall itself is not affected; bays are checked for structural support.

Modern glazing typically lasts 20 to 35 years. Guarantees on frames, units and fitting are set out on your quote.

On our guide, triple glazed uPVC windows cost £695 to £1,695 each, fitted and inc VAT. A 3-bed semi with 9 windows and a front door is £9,395 to £11,795.

Usually 20 to 30% more for the same window, within a UK range of about 15 to 40%.

Yes, for windows, doors and glass-only jobs. The surveyor measures every opening and you get a written quote with no obligation. For island and some remote districts we confirm survey arrangements and any travel cost first.

Yes, for the specification shown. If anything extra is found on the day, it is agreed with you before any work is done.

Yes, 20%. The 0% VAT rate for energy-saving materials does not cover glazing.

Rarely. ECO4 runs to 31 December 2026 and seldom funds glazing; some local schemes include glazing in rare cases. See our regulations and funding guide.

The deposit and payment stages are set out on your quote and in our terms before you agree to anything.

Usually not for like-for-like windows on a house. In England, flats, Article 4 areas and listed buildings are the exceptions; the rules differ in Wales, Scotland and Northern Ireland, and our regulations guide covers each nation.

In England and Wales, yes: the work is certified by a competent person scheme installer or approved by building control, and you receive a certificate.

If your old windows had them, yes, at least as large. If not, ventilation must be no worse than before.

No. Neither the current rules nor the Future Homes Standard require it.

Replacing original windows usually needs listed building consent and is often refused. Secondary glazing is the usual alternative.

Usually not usefully. Most frames take up to about 28 mm units, and a triple unit that thin performs no better than good double glazing.

uPVC for value, aluminium for slim frames and big panes, timber for period homes, alu-clad timber for low upkeep and high performance.

A little on its own. A laminated acoustic pane makes the bigger difference.

Many can, but some sash systems limit the unit thickness. We tell you the real U-value before you order.

Yes where the door is mostly glass, such as French, sliding and bifold doors, or front doors with side panels.

A whole house usually takes 1 to 4 days. Each opening is closed up the same day.

Typically 4 to 6 weeks for uPVC, 5 to 7 for aluminium, 6 to 10 for timber and 8 to 12 for alu-clad timber, from survey.

Yes. Old frames and glass are removed and taken away as part of the price.

Fitting involves cutting out old frames, so there is some dust. Floors and furniture are covered and the reveals are made good.

Installation teams working for us, under our written quote and terms. Your contract is with S&K Property Investments and Improvement Ltd.

We arrange surveys and fitting across England, Wales, Scotland and Northern Ireland. Islands and some remote areas are by arrangement.