Catherine Katzka's £100,000 retrofit of her Sydenham townhouse was supposed to make her home more energy-efficient and warm in winter. But as last month's 35C sunshine showed, it failed to prevent overheating – temperatures inside reached a sweltering 28C after just three days. The owner of the 1960s property had hoped to reduce her carbon footprint and energy bills, but instead found herself regretting not adding air conditioning.
The mechanical ventilation heat recovery (MVHR) system, designed to circulate fresh air and recover heat in winter, proved ineffective during the hottest parts of the day. London's urban heat island effect exacerbated temperatures indoors, leaving Katzka feeling uncomfortable in her own home. The retrofit also featured triple-glazed windows, photovoltaic panels, an air source heat pump, and external blinds – measures that have led to a 70% reduction in energy bills, but offered minimal summer benefits.
Katzka's experience is not unique – many Londoners are struggling with overheating in their homes, particularly those living in older properties. The 2022 heatwave saw record temperatures across the UK, and resulted in over 3,271 heat-related deaths in England, with 387 of these occurring in London.
Experts warn that over a million existing properties in London will require retrofitting for heat in the medium to long term – but funding is a major concern. Dan Bicknell, climate adaptation manager at the Greater London Authority (GLA), estimates there's a 'huge funding gap' for such programmes. The GLA is expected to publish its Heat Risk Delivery Plan this summer, outlining a city-wide strategy for managing extreme heat.