“Our ability to trust that our homes will keep us safe from the outside is under threat,” the geographer Sam Johnson-Schlee writes in Hot House, his recent book on how heat has transformed domestic life. This summer, high temperatures have become inescapable. People have coped with makeshift solutions: keeping curtains drawn, placing foil over windows or – for those who can afford one – plugging in an air-conditioning unit. Planning experts warn that, with only about half of councils requiring new buildings to include cooling strategies, many homes will become “death traps” as temperatures rise. Britain’s homes weren’t built to cope with this. The country’s historically mild climate allowed developers to build houses without insulation, while industrialisation supplied plentiful coal to burn when temperatures dropped. Many homes are consequently drafty in winter and sweltering in summer. Unlike those in Mediterranean climates, British homes lack shutters and shaded communal spaces. While Ildefons Cerdà, Barcelona’s masterplanner, was designing housing blocks with cool courtyards and chamfered edges to allow breezes to flow, Britain’s Victorian builders were throwing up …