There’s been a lot of noise this year about new building regulations and the Future Homes Standard, and we’re increasingly asked the same question by homeowners: “Do I now have to buy triple glazing?”
The short answer is no. But the rules are worth understanding, because they affect what any reputable installer should be fitting in your home. As a company that manufactures its own PVCu windows here in Swindon, we thought it was worth setting out what’s actually changed, and what hasn’t.
The rules for replacement windows today
If you’re replacing the windows in an existing home, the requirement comes from Part L of the Building Regulations. Since June 2022, replacement windows have needed to achieve either:
- a U-value of 1.4 W/m²K or better, or
- a Window Energy Rating (WER) of Band B or above
A U-value measures how quickly heat passes through the window, so lower is better. For context, the single glazing in older homes can have a U-value of around 5, and early double glazing from the 1980s and 90s often sits around 3. A modern double glazed window comfortably beats the 1.4 requirement, thanks to better frames, argon filled units and low emissivity coatings.
Any installer registered with a competent person scheme such as FENSA will certify that your new windows meet these standards, and you’ll get documentation to prove it, which matters when you sell your home.
So what’s changing in 2026 and 2027?
The Future Homes Standard, which the government published in March 2026, is the big regulatory change everyone is talking about. It comes into force in March 2027 and it will make newly built homes significantly more energy efficient, with tougher targets across heating, hot water and insulation, including more demanding window specifications for new builds.
Here’s the key point: the Future Homes Standard applies to newly built homes. If you’re replacing the windows in your existing house, the requirement remains a U-value of 1.4 W/m²K or WER Band B, exactly as it has been since 2022.
It’s fair to say the direction of travel is towards tighter standards, and requirements for replacement windows may well tighten in the years ahead. But nothing in the 2026 announcement forces homeowners to fit triple glazing.
Double vs triple glazing: an honest comparison
With that cleared up, is triple glazing worth considering anyway? Sometimes. Here’s how they compare.
Warmth. Triple glazing adds a third pane and a second insulating cavity, which typically brings the U-value down to around 1.0 or below, compared with roughly 1.2 to 1.4 for good double glazing. That’s a real improvement, but it’s a much smaller step than the leap from old single or early double glazing to modern double glazing.
Noise. Triple glazing can help with noise, though the benefit depends more on the glass thicknesses and the gaps between panes than on the number of panes alone. If noise is your main concern, acoustic glass in a double glazed unit is often the more effective option, and we can advise on this.
Cost. Triple glazing typically costs noticeably more than the equivalent double glazed window. Whether the extra energy saving pays that back depends on your home, your heating and how long you plan to stay.
Weight. A third pane makes each window heavier, which puts more demand on frames and hinges. Because we manufacture our own windows, we can make sure the frame is properly specified either way.
Our advice
For most Swindon homes, modern A rated double glazing is the sensible choice: it exceeds the current regulations, transforms comfort compared with older windows, and costs meaningfully less than triple glazing. Triple glazing earns its keep in specific situations, such as very exposed properties, homes near busy roads where noise and heat loss are both issues, or owners who simply want the highest specification available.
Either way, you shouldn’t be pushed into a specification by scare stories about new regulations. The right answer depends on your home, and a good installer will talk you through it honestly.
Talk to the people who make them
Every PVCu window we fit is made by us in Swindon, installed by our own teams rather than subcontractors, and covered by our 10 year guarantee. If you’d like an honest recommendation for your home, get a free quote or call us on 01793 480155.
Regulations summarised here are as published at the time of writing in 2026. If your project involves a new build or an extension, different requirements apply, and we’re happy to talk you through them.
