More than 600 housing assessments flag Excess Heat hazards – what the findings mean for leaseholders

For people living in leasehold flats, addressing overheating can be more complicated than making changes to a freehold house.

Responsibility for different parts of a leasehold building depends on the terms of the lease. While leaseholders will typically be responsible for much of the interior of their own flat, areas such as the roof, external walls and communal parts of the building will usually sit with the freeholder.

Measures that could help tackle overheating may therefore require the involvement or consent of the freeholder or managing agent. This can include changes to windows, external walls, ventilation routes or external equipment.

The cooler months can provide an opportunity for residents, landlords and building managers to identify which flats struggled during the summer and establish whether the problem can be addressed within the property itself or whether wider changes to the building need to be considered.

The research found councils had reported 102 Improvement Notices, 20 Prohibition Orders and 29 Hazard Awareness Notices where Excess Heat was among the hazards concerned. A further two Emergency Prohibition Orders, seven Emergency Remedial Actions, four civil penalties and three prosecutions were also reported.

Under HHSRS, local authorities must take enforcement action when Category 1 hazards are identified and can also act on Category 2 hazards.

This can be particularly relevant for leaseholders who rent their flat out, as they also have responsibilities as landlords to ensure the property is safe. Where an overheating problem involves a part of the building controlled by the freeholder, the leaseholder may therefore need to work with the freeholder or managing agent as well as responding to concerns raised by their tenant.

Bradford Council identified 114 Excess Heat hazards across the periods studied, while Barnet reported 47, including 19 at Category 1 level, and Bristol recorded 57, including 10 Category 1 hazards.

Some councils have also recorded a rise in cases during 2026. Bournemouth, Christchurch and Poole Council identified 10 Excess Heat hazards from 58 assessments between April and the end of July, compared with just two across 334 assessments during the previous three full financial years combined.

Daniel Southern, Managing Director at Cut Plastic Sheeting, said: “After the temperatures we experienced this summer, autumn and winter are a good opportunity for people living in and managing flats to look at which properties and rooms struggled most and why.

“Flats can present particular challenges because the person living in the property may not have complete control over every part of the building. If the problem appears to involve windows, ventilation, external walls or another part of the building, it is worth checking the lease and speaking to the freeholder or managing agent before assuming changes can be made independently.”