UK Homes Overheating: Passivhaus Offers Cool Solution

As the UK braces for potentially its hottest summer on record, homeowners are struggling to stay cool, with over half of UK homes already at risk of overheating. This trend is projected to worsen significantly by 2050.

An architect-designed 1960s ex-council house in south London demonstrates a successful adaptation to warmer summers. This home, retrofitted to the Passivhaus standard, maintained a temperature 10C cooler than outside during a 35C day, proving that effective home design can negate the need for air conditioning.

The Passivhaus standard, originating in Germany, focuses on creating airtight buildings that maintain a constant internal temperature, drastically reducing energy use – estimated at up to 90% less than typical homes. The retrofitting process involved extensive insulation, eliminating thermal bridges, and installing triple-glazed windows.

While Passivhaus retrofits offer substantial energy savings, estimated at 88% in this case, the cost can be considerable. The Baeli residence's retrofit cost approximately £80,000, with windows being the most expensive component. Spreading the cost over a decade made it manageable for the homeowner.

Building new homes to the Passivhaus standard is more cost-effective, ranging from 2% to 5% additional construction cost. New regulations like the Future Homes Standard in England and ongoing consultations in Scotland are moving building requirements closer to Passivhaus levels.

Despite efforts in new construction, an estimated 80% of the UK's housing stock in 2050 already exists today, necessitating millions of retrofits. While government support for insulation measures has faced issues, simple strategies like shading windows can still make a significant difference in managing indoor temperatures during heatwaves.