LUTON, UK. July 2nd, 2025 – Secondary glazing is becoming a popular choice for people who want warmer, quieter homes without losing the charm of their original windows, according to new data.
Secondary glazing involves adding a slim, internal window pane to your existing windows. It improves insulation and significantly reduces noise — without needing to remove or replace your original windows. It’s particularly useful for older properties and listed buildings where double glazing isn’t allowed.
“In the last couple of years, interest in secondary glazing has really taken off,” says Colin, founder of Colin’s Sash Windows, which supplies secondary glazing and timber sash windows across the UK.
“It’s discreet, it’s effective, and it’s often half the cost of full window replacements.”
80 million windows across the UK still don’t meet modern energy standards (GGF / British Glass, 2023), with one in ten still having single glazing (English Housing Survey). Homes with single-glazed windows can lose up to 20% of heat through the glass (Energy Saving Trust).
Secondary glazing can reduce outside noise by up to 80%, making it ideal for homes near roads, railways or airports (Colin’s Sash Windows). In noisy urban areas and homes under flight paths, secondary glazing is being installed to block traffic and aircraft noise, often supported by local authority or airport schemes.
Around 1 in 10 UK homes still have single glazing — that’s nearly 3 million properties, many of them character homes .
For landlords, it’s not just about energy ratings — it’s about tenant satisfaction and retention.
“We often hear from landlords who are losing tenants because flats are too cold or too noisy,” Colin said. “Secondary glazing is a cost-effective way to fix both problems, protect rental income, and improve the property’s EPC rating.”
With tougher energy efficiency regulations on the horizon for rental properties, insulating windows is becoming a priority. Secondary glazing can help raise EPC scores and future-proof homes without major renovations.
In London, homeowners are turning to secondary glazing in record numbers, especially in conservation areas where traditional windows must be preserved.
Historic cities like York, Bath and Edinburgh are seeing strong demand as property owners seek discreet ways to improve comfort without breaching planning rules.
Colin added: “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.”
ENDS