Double Glazing Guides
Plain-English advice on what double glazing costs, how the styles differ and how to get a fair price in 2026.
These guides are written to answer one question at a time and to tell you what to do, not to sell you windows. Start with the money questions if budget is your worry, the style questions if you are not sure what suits your home, or the technical questions if you want to understand the spec on a quote. When you are ready to put numbers to it, the calculators turn your choices into a price range, and the costs hub holds the full 2026 price tables.
Cost Per Window
What a single window costs fitted, plus supply-only versus fully fitted.
Is Double Glazing Worth It?
When the savings and comfort justify the spend, and when to wait.
Casement Windows Explained
The most common UK style: how it works, what it costs and who it suits.
Sash Windows Explained
Vertical sliding windows for period homes, in uPVC or timber.
U-Values Explained
What the U-value means and the 1.4 W/m²K limit under the building regulations.
FENSA Explained
Why the FENSA certificate matters and what it proves about your install.
How to Avoid Being Overcharged
The sales tactics to watch for and how to read a quote like an installer.
How Long Does It Last?
Realistic lifespans for frames and sealed units, and when misting starts.
Before you buy
Two related topics sit just outside this hub. If you are weighing one frame or spec against another, the comparison guides put the options side by side, including double versus triple glazing. And if you are on a low income, check whether you qualify for help before you pay: our double glazing grants guide explains the 2026 schemes, though only around 15% of households are eligible.