London landlords are being put on notice over overheating risk after City Hall published its first Heat Ready London plan, warning that around one million homes in the capital may already be at high risk of overheating.
The plan was launched as London headed into another severe heat event, with City Hall citing more than 1,300 schools, 60 hospitals and 351 care homes in high heat-risk areas. For landlords, the immediate issue is not a new legal deadline, but a clear policy shift: overheating is moving from a design concern into a mainstream housing risk that councils, policymakers and tenants are far more likely to scrutinise.
That matters for private landlords because the same stock already under pressure on energy efficiency and repair standards may now face tougher questions about summer performance too. In practical terms, older flats, loft conversions and heavily glazed homes look especially exposed if tenants start reporting heat-related hazards more aggressively.
One million London homes flagged as overheating risk
City Hall said the new plan focuses on protecting people most at risk, retrofitting buildings, widening access to cooling spaces and improving infrastructure resilience. The Mayor also pointed to the London Plan requirement for new homes to reduce overheating through shading, ventilation and smarter design rather than relying on energy-hungry cooling.
For existing rental stock, the harder issue is retrofit. Measures such as external shading, better ventilation, solar control and roof-level heat management can be expensive or awkward in converted or leasehold property. Yet the direction of travel is clear. Once a risk is formally mapped and tied to public health, it rarely stays outside housing enforcement for long.
This follows Landlord Knowledge’s report on poor EPC rentals facing the biggest July bill jump, which highlighted how weaker-performing homes already carry higher running-cost pressure. The latest London heat plan adds a summer resilience angle to that debate, suggesting landlords may soon need to think about heat control as well as winter efficiency.
Why overheating is becoming a landlord issue
City Hall said London recorded an all-time May high of 35.1C this year and estimated the 2022 heatwaves cost the capital £1.5 billion. It also said London sees nearly 4,000 additional hospital attendances during hot weather each summer and around 300 extra preventable deaths each year.
Those figures help explain why overheating is no longer being treated as a niche climate topic. Landlords have already seen how hazards move quickly from guidance to enforcement once public risk is widely accepted. The same pattern could emerge here, especially where vulnerable tenants, upper-floor flats or poorly ventilated conversions are involved.
There is also a more immediate commercial point. Homes that are visibly uncomfortable in hot weather are harder to let, more likely to trigger complaints and more likely to need reactive spending at the worst moment. London landlords trying to hold rent levels in a more selective market may find that overheating resilience becomes part of the offer.
A wider policy squeeze is also building. Recent pressure for faster Decent Homes rules and ongoing EPC debate mean landlords are dealing with overlapping standards rather than one neat compliance line. City Hall’s plan does not create a direct new duty for private landlords today, but it does make overheating much harder to dismiss as a tenant lifestyle issue.
For the primary source, City Hall’s full Heat Ready London announcement sets out the one million homes estimate and the retrofit focus for existing buildings.
What this means for landlords
- If you own upper-floor or heavily glazed homes: review shading, ventilation and tenant complaint history before the next heatwave exposes weak spots.
- Watch for: overheating to be folded more directly into wider housing quality and hazard enforcement.
- Bottom line: in London at least, heat resilience is moving closer to the mainstream compliance list.
Editor’s view
Overheating is following the familiar path from technical issue to political one. Once that happens, landlords who wait for a formal deadline usually end up paying more than those who act early.
Author: Editorial Team – UK landlord & buy-to-let news, policy, and finance
Published: 7 July 2026
Sources: London City Hall
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