Portable air con ‘costly stopgap’ for overheating UK homes, expert warns

A spike in consumer interest for air conditioning units following record temperatures this summer has highlighted the vulnerability of UK housing stock to extreme summer heat.

According to a report by the UK Parliament Environmental Audit Committee, rising heatwaves are driving up domestic demand for active cooling units, putting additional strain on the national power grid during summer heat peaks. As a result, demand for temporary cooling appliances reached peak levels during recent heatwaves. However, building standards specialists warn that reliance on plug-in appliances offers a costly stopgap for properties suffering from poor thermal retention.

Nick Allen, spokesperson for West Midlands firm Reliant Windows, said: "When a heatwave hits, buying a portable AC unit feels like the quickest fix. But without proper insulation, it’s the equivalent of leaving the fridge door wide open while trying to keep your kitchen cold. You are spending significant money on electricity to generate cool air, only for it to bleed right through inefficient glass and worn-out window seals."

According to Met Office figures, recent temperature records were surpassed during an unprecedented June heatwave that saw mercury levels exceed 37°C across parts of the country. The sustained high temperatures have driven households to seek immediate cooling solutions, though energy experts point out that inefficient glazing and degraded window seals mean cooled air quickly escapes.

Unlike winter heat loss, summer thermal transfer occurs when radiant solar energy penetrates single glazing or aged double-glazed units without low-emissivity coatings. Portable air conditioning units typically require an exhaust hose to be vented through an open window, which can inadvertently allow warm ambient air back into the living space, compounding energy usage.

GOV.UK home energy efficiency guidance recommend inspecting window perimeter seals for cracking or flattening, assessing whether interior glass surfaces retain excessive heat under direct sunlight, and evaluating uninsulated conservatory roofing, which can significantly elevate internal temperatures during prolonged heatwaves.