The Glass and Glazing Federation (GGF), an industry body, has published research stating that 98 per cent of homes are losing energy through underperforming windows1. The figure appeared on the federation's Environmental Hub in a post dated 20 November 2023, alongside the claim that UK homes have been "branded the leakiest in Western Europe when it comes to heat loss"1.
The GGF describes the UK housing stock in broad terms on the same page. It states that across the UK there are "some of the oldest and leakiest homes across the whole of Europe when it comes to heat loss", adding that homes are consequently hard to heat in winter and difficult to cool in summer, which it says ultimately affects the cost of energy bills1. The federation does not set out on the page how the 98 per cent figure was calculated, which window types or vintages it covers, or the sample and method behind the homeowner research it refers to; those details have not been reported1.
The page also links to earlier GGF research headlined "Six Million UK Homeowners Don't Know Their Property's EPC Rating"1. That item is presented as research conducted with UK homeowners, but the Environmental Hub does not reproduce its findings in full1.
"Across the UK, we have some of the oldest and leakiest homes across the whole of Europe when it comes to heat loss."
The federation also points homeowners towards Window Energy Ratings as a comparison tool, stating that they "let you compare the energy efficiency of different window products"1. Separately, it refers to a free uPVC Recycling Scheme, which it says "has been put in place to lend a reassuring hand to all UK homeowners"1. No figures for the scheme are given on the page1.
| Claim | Figure | Date given |
|---|---|---|
| Homes losing energy through underperforming windows | 98% | 20 November 2023 |
| UK homeowners who do not know their EPC rating | Six million | Not stated on the page |
Why it matters for households
Heat escaping through the building fabric is the starting point for a home's energy independence: the less that leaves through the windows and doors, the less has to be bought and paid for to keep rooms warm. The GGF's framing places the UK stock among the oldest and leakiest in Europe, which links the physical condition of a home directly to running costs and to how much of its heating a household effectively pays for twice1.
For householders, the practical questions raised by the 98 per cent figure are about their own property rather than the national average: the age and type of glazing, whether it has been rated, and what the home's EPC says. The GGF's own earlier research suggests a gap in that knowledge, with six million homeowners reported not to know their EPC rating1. The federation's stated position is that window products can be compared on energy efficiency through Window Energy Ratings1.
None of this is a statement about any individual home. The published material does not break the 98 per cent down by nation, tenure, property age or glazing type, so it cannot be used to infer what any particular household is losing1. Wider context on how the UK stock performs sits in the site's guide to the energy efficiency of the UK housing stock, and on the general pathways of heat loss in where a UK home loses heat.
What happens next
No next steps, targets or follow-up publication dates are set out on the GGF's Environmental Hub page1. The page carries a link to a "Homes of Tomorrow" section and to an energy calculator, but no timetable for either is given1.
Sources1 cited
- Environmental Hub, ggf.org.uk