The number of commercial buildings being converted into homes has risen sharply since planning rules were relaxed in 2021, prompting warnings that more attention needs to be paid to the risk of overheating as temperatures continue to rise.
Analysis of government planning data by Zurich UK shows that applications to convert offices into residential properties in England increased from 1,025 in 2022 to 1,623 in 2025, a rise of 58%.
The insurer warns that while office-to-residential conversions can help increase housing supply, some buildings were not originally designed for round-the-clock residential occupation and may struggle to cope with hotter summers.
The warning comes as the UK experiences increasingly frequent periods of extreme heat. This year saw the hottest May since 1922, while temperatures in parts of the country have continued to climb during June.
Zurich argues that developers and policymakers need to consider climate resilience when converting commercial buildings, particularly as the Government seeks to accelerate housing delivery and meet its target of building 1.5 million homes during this Parliament.
Among the concerns highlighted are poor ventilation, large areas of glazing, limited shading, outdated building fabric and the urban heat island effect, all of which can increase the risk of overheating. The insurer also notes that some converted buildings may fall outside modern overheating standards, raising questions about their suitability for future climate conditions.
Megan Dunford, Zurich’s head of large and complex property claims, said: “These challenges expand well beyond isolated periods of hot weather. While global climate patterns such as El Niño may amplify temperatures in the short term, the broader trends point to more prolonged and sustained heat events across the UK.
“Commercial buildings are generally designed to different operating tolerances than residential properties, and sustained temperature variation can place material stress on the building fabric. This increases the risk of thermal expansion and contraction, which may contribute to cracking, subsidence, and ultimately escape of water incidents. Over time, this not only undermines building safety and durability, but also exposes residents to higher maintenance costs and reduced living standards.”
London remains particularly vulnerable to rising temperatures, with concerns that many homes and converted buildings are not well equipped to cope with prolonged periods of hot weather.
Research by academics at the Grantham Research Institute on Climate Change and the Environment at the London School of Economics found that around half of UK homes are already at risk of overheating. Under a scenario in which global temperatures rise by 2°C, that figure could increase to 90% of homes.
While building regulations now include measures to address overheating in new-build properties, much of the existing housing stock is exempt. This is significant given that the UK has some of the oldest and least energy-efficient homes in Europe.
Overheating is not only a comfort issue. The Climate Change Committee estimates that heat-related deaths in the UK could increase by around 250% by the 2050s if adaptation measures are not taken.
Zurich says developers converting commercial buildings into homes should consider measures such as improving ventilation, reducing solar heat gain, upgrading building fabric and carrying out overheating risk assessments. The insurer also argues that developments should be designed with future climate conditions in mind rather than simply meeting current regulatory requirements.
Chantelle Davidson, Zurich resilience solution’s head of property risk engineering, commented: “The way buildings are constructed and how that interacts with a changing climate is becoming even more crucial. Yet, this often overlooked. Many commercial buildings were not originally intended for residential use, with materials, façades and systems designed around operational needs rather than the expectations of people living in them day to day. As a result, some features can make it more difficult to maintain a consistently comfortable indoor environment. This makes it particularly important to take a forward-looking approach at the point of design.
“Careful decisions around layout, ventilation, material choice and overall performance can make a significant difference when these properties are converted in how well these buildings adapt over time. By embedding resilience early, developers can help ensure converted homes can remain efficient and fit for purpose as wider environmental changes impact the built environment.”
Read the orginal article: https://propertyindustryeye.com/too-hot-to-live-in-100000-homes-face-heatwave-risk/
