keeping cool

FOR A HOME THAT DOESN'T OVERHEAT IN THE SUMMER MONTHS BUT STAYS WARM IN WINTER, THE ANSWER IS IN THE ARCHITECTURE

- FEATURE Hugh Metcalf

The modern appetite for glass box extensions and homes with vast swathes of glazing might be great for creating a connection to the great outdoors and flooding spaces with natural light, but there's one big drawback if poorly conceived. Overheating. Some time ago, I visited a London home with a brand new fully glazed side return extension on a hot day in July, where the owner was clearly finding out first hand that overheating hadn't been part of the calculations.

It's no secret that we've been experiencing record-breaking temperatures during the summer months, and those homes with majority-glass extensions designed by architects who haven't weighed up the risks of overheating will suffer most in a heatwave. Fortunately, overheating is now a part of Building Regulations in the UK, meaning a build or renovation won't be compliant unless it meets strict rules. This might mean your architect having to reduce the number of south-, east- and west-facing windows, unless properly counteracted.

So, why do homes overheat? 'The key consideration is solar gain, and ensuring this is really well managed,' architect Tom Rutt of TR Studio tells me. Solar gain is the increase in temperature in a building, caused by solar radiation basically, heat from the sun. The amount of solar gain a home receives will depend on a few factors, but the most important is the aspect of your home.