Secondary glazing is rapidly gaining traction among UK homeowners who want to improve warmth and peace within their homes—without compromising the original look of their windows, according to new industry data.
This insulation method involves placing a slim glass panel inside the existing window frame. It retains the home’s historic features while significantly improving thermal performance and reducing outside noise. It’s especially well-suited to older or listed homes that can’t use conventional double glazing.
“In the last couple of years, interest in secondary glazing has really taken off,” says Colin, founder of Colin’s Sash Windows, which provides traditional and secondary glazing solutions across the UK.
“It’s discreet, it’s effective, and it’s often half the cost of full window replacements.”
Figures from GGF and British Glass (2023) show that approximately 80 million windows in the UK do not meet today’s energy standards. Meanwhile, the English Housing Survey confirms that one in ten homes still has single glazing—potentially leading to a 20% loss of indoor heat through windows alone (Energy Saving Trust).
Secondary glazing can also cut noise by up to 80% (Colin’s Sash Windows), making it a strong option for households located near main roads, train tracks or airports. Many installations in these areas are supported through local council or airport-backed grant programmes.
There are still nearly 3 million single-glazed homes in the UK—many of them period properties where window upgrades face strict regulations.
For landlords, Colin says secondary glazing can also improve tenant satisfaction.
“We often hear from landlords who are losing tenants because flats are too cold or too noisy,” he said. “Secondary glazing is a cost-effective way to fix both problems, protect rental income, and improve the property’s EPC rating.”
With enhanced energy efficiency rules for rented properties on the horizon, landlords and property owners are under increasing pressure to boost their EPC scores. Secondary glazing offers a fast, minimally invasive way to do so.
In conservation areas across London, demand is soaring, with homeowners looking for solutions that preserve the original appearance of their windows. Likewise, in heritage-rich locations like Edinburgh, Bath, and York, secondary glazing is emerging as a popular option that complies with planning requirements.
“Secondary glazing used to be niche, but now it’s becoming mainstream. People want warmer, quieter homes and this is a smart, affordable way to get there,” Colin concluded.
