PRS homes fall short on thermal comfort standards as HHSRS rules come into force

More than 441,000 private rented homes fail thermal comfort standards, according to new data.

Research by Inventory Base reveals around 40% of PRS homes fall short as updated Housing Health and Safety Rating System (HHSRS) rules came into force last week.

The government announced landlords could face on-the-spot fines of £7,000 for severe damp and mould under new council powers.

How homes perform during periods of extreme summer heat

The new HHSRS system, which came into force last week, reduces hazard categories from 29 to 21 and replaces A–J ratings with a high, medium and low risk system and places greater emphasis on both excessive cold and overheating risks.

Inventory Base warns the findings show growing concerns around temperature-related housing safety, particularly as UK summers become hotter.

Sián Hemming-Metcalfe, operations director at Inventory Base, said: “For many years, conversations around housing quality have rightly focused on keeping homes warm, dry and energy efficient during the winter months. But as the UK’s climate changes, property professionals are increasingly having to consider how homes perform during periods of extreme summer heat as well.

“June’s prolonged heatwave, which saw temperatures exceed 35°C in parts of the country, has brought that challenge into sharp focus. While thermal comfort deficiencies under the revised Housing Health and Safety Rating System (HHSRS) are distinct from overheating hazards, both highlight the growing importance of ensuring homes remain safe and habitable throughout the year.

“The revised HHSRS reflects a broader understanding of housing safety. It is no longer enough to think only about protecting occupants from the cold. Landlords, letting agents and property professionals must now consider how properties perform across all seasons, particularly as hotter summers become more frequent.”

Inadequate ventilation

The firm warns that excess heat hazards stem from excessive solar gain, poor shading, inadequate ventilation, and building features that prevent safe indoor temperatures.

The news comes as the government has confirmed all private and social landlords will need to meet the Decent Homes Standard (DHS) by 2035.