The Glass and Glazing Federation (GGF) published research on 20 November 2023 finding that almost all UK windows would not meet current standards if they were installed today, and that UK homes are three times less efficient than those in Germany1.
The federation's figures put heat lost through old, draughty windows at more than a fifth, 24 per cent, of a home's heat energy1. It cites National Energy Agency estimates that 6.6 million households are currently in fuel poverty, described as being unable to afford to heat their homes to the temperature needed to keep warm and healthy1. The research also estimates that the annual cost saving from replacing pre-2002 windows with current standards could reach £4.1 billion1.
"if almost all (98%) of the UKs windows were installed today, they wouldn’t be up to standard"
The GGF describes UK homes as the leakiest in Western Europe for heat loss, and says replacing windows should be "front and centre" of future energy efficiency schemes1. It frames the findings around fabric first upgrades, naming windows and further wall insulation as measures that prevent heat escaping through walls, windows and doors1. The announcement does not set out how the 98 per cent figure was calculated, which window vintages or ratings were assessed, or how the £4.1 billion saving was derived; none of that has been reported1.
| Measure in the GGF research | Figure given |
|---|---|
| UK windows that would fail current standards if installed today | 98% |
| Heat energy lost through old, draughty windows | 24% |
| Households in fuel poverty (National Energy Agency estimate) | 6.6 million |
| Annual saving from replacing pre-2002 windows | £4.1 billion |
Why it matters for households
Windows are one of the routes by which a home loses heat, alongside walls, roofs, floors and doors, so their condition bears directly on how much energy a household must buy to stay warm. The GGF's 24 per cent figure places roughly a quarter of a home's heat energy at the window opening, and its comparison with Germany suggests the gap between UK and comparable European housing stock is wide1. For a household, the practical link is between the age and airtightness of its glazing and the size of its bills, which is why the federation ties the issue to fuel poverty and to the £4.1 billion national saving it estimates1. The research does not report what any individual home would save, nor the cost of replacement, so the household-level payback is not established in what has been published1. Window performance is graded through Window Energy Ratings and Glazing Standards, and the wider picture of where heat leaves a property is set out in Where a UK Home Loses Heat and Why It Matters First and How much heat is lost through windows and doors?.
What happens next
The GGF says replacing windows should be central to future energy efficiency schemes, but no scheme, funding route or timetable is named in the announcement1. No dated next steps have been reported1.