Key takeaways
- The Met Office has projected that UK temperatures could reach 45°C by 2056, based on around 2.5°C of global warming.
- Most UK commercial buildings were designed for heat retention, not heat management, making them structurally unprepared for a hotter climate.
- Overheating carries potential risks for commercial buildings: productivity loss, health and safety obligations, losing tenants, and reduced asset value.
- Fabric improvements, natural cooling, and modern building systems can all reduce overheating risk, with the buildings being refurbished today still being in use in 2056.
What does the data tell us about future heat risk in the UK?
The 45°C figure comes from a scenario published by the Met Office in June 2026, developed to mark the 50th anniversary of the 1976 summer heatwave. The scenario, described as scientifically plausible under approximately 2.5°C of global warming, is not a specific forecast. It is an example of how a comparable heat event would unfold in the 2050s given current emissions projections.
Furthermore, the numbers behind it are significant. The scenario projects peak temperatures of 45°C in England, 41°C in Wales, and 38°C in Scotland, sustained over a two-week period. Average UK summers have already warmed by around 1.4°C since 1976. Five British summers have now been hotter than that year, with 2025 the warmest on record to date.
The direction of summer temperatures is already visible in the data, and in the decarbonisation compliance timeline that commercial property owners are already navigating.
Why are UK buildings particularly vulnerable to overheating?
A large majority of UK commercial buildings were designed for a cool, damp climate, with the priority for most of the 20th century being heat retention through solid walls, small windows, minimal ventilation, and little or no mechanical cooling. Those design choices, which served buildings well in mild summers, create serious problems when temperatures rise sharply.
Those same fabric characteristics that keep warmth in during winter trap heat in during summer. Poor airtightness, a lack of shading, and low amounts of cross-ventilation mean that internal temperatures in many commercial buildings can rise to high heat.
The specific vulnerabilities include:
- Solid brick or stone construction that absorbs heat during the day and releases it slowly overnight.
- Single-glazed or poorly positioned windows that let heat in but cannot release it effectively once the sun goes down.
- Flat roofs and large unshaded facades that absorb radiated heat directly.
- Ageing or no mechanical ventilation systems that cannot cope with sustained high temperatures.
- Little or no green infrastructure, such as trees, green roofs, or planted facades.
These design flaws are the physical reality for a large proportion of the UK's existing commercial building stock, much of which will still be in active use in 2056.
What does building overheating risk mean for property owners and occupiers?
The consequences of a poorly performing building in a heatwave are both physical and commercial.
Productivity and health
In a sustained heat event, buildings without adequate cooling become difficult to work in, with employers having a legal obligation under health and safety law to maintain a reasonable working environment.
Occupier retention
Tenants choosing between properties will increasingly factor thermal comfort into their decisions, just as they already factor in EPC ratings and sustainability credentials. A building that overheats in summer is harder to let, which can affect both occupancy rates and achievable rents.
Asset value
Lenders and investors are paying closer attention to climate-related physical risk. A building that performs poorly carries a potential future heat risk, particularly as overheating standards tighten. The hidden costs of delaying decarbonisation include buildings declining in competitiveness in a market that is only moving in one direction.
Regulatory exposure
Overheating risk is already reflected in Part O of the Building Regulations, which applies to new residential buildings. Commercial buildings are not yet subject to equivalent mandatory standards; however, the regulatory direction is clear. Buildings that cannot demonstrate an ability to stay cool in high temperatures face growing pressure as standards increase.
How does decarbonisation reduce the risk of buildings overheating?
The relationship between decarbonisation and overheating is often missed. Reducing a building's carbon footprint and reducing its vulnerability to heat are not separate objectives. The same fabric improvements that cut energy consumption also reduce the risk of the building becoming dangerously hot.
A fabric first approach addresses the buildings outer shell before mechanical systems. Better insulation, improved airtightness, and high-performance glazing with solar control all reduce the rate at which heat enters the building in summer. Shading, whether fixed, adjustable, or planted, prevents solar gain before it becomes an internal problem.
The measures that make the greatest difference include:
- High-performance glazing with solar control coatings, which reduce radiated heat gain without significantly reducing daylight.
- External or internal shading systems, including blinds, brise soleil, and planted facades, which intercept solar radiation before it reaches the glass.
- Improved roof insulation and cool roof coatings, which reduce heat transfer through one of the most exposed surfaces in a commercial building.
- Mechanical ventilation with heat recovery (MVHR), which provides controlled fresh air without opening the building to unfiltered external heat.
- Heat pumps and modern HVAC systems, which provide both heating and cooling more efficiently than legacy gas-based plant.
- Green roofs and planted areas reduce the way built-up areas trap and hold heat, providing natural insulation.
A thorough energy audit will identify which of these measures will have the greatest impact, both for reducing energy consumption and for managing overheating risk for a building. The two conversations should be happening at the same time.
It is also worth considering a whole life carbon assessment when planning significant refurbishment work. This ensures that the carbon produced during construction is accounted for alongside the building's running performance, giving a complete picture of its long-term environmental impact.
Why is now the right time to act on climate resilient buildings?
The buildings being refurbished and upgraded today will still be in active use in 2056. Decisions made now about insulation, glazing, ventilation, and building systems will determine how those buildings perform in a climate that is likely to get hotter than the one we are experiencing today.
Acting between heat events is significantly more cost-effective than responding to them. Emergency cooling installations, emergency maintenance, and accelerated tenant loss all carry costs that far exceed the price of planned, systematic improvement. The case for climate resilient buildings in the UK is not one of environmental ambition, it is one of sound asset management.
There is also a financing dimension. Green mortgage products and sustainability-linked lending are increasingly available to property owners who can demonstrate credible improvement programmes. Buildings with strong energy performance credentials, and clear plans to improve them further, are better positioned to access that capital at competitive rates.
The decarbonisation compliance timeline for UK commercial buildings runs to 2035 and beyond. Much of the work required to meet those standards and to build genuine climate resilience overlaps substantially. Starting that work now means doing it once, deliberately, with the benefit of professional advice.
How BTG Eddisons can help manage climate change risk in commercial properties
BTG Eddisons is a full-service property consultancy with specialist expertise in commercial building decarbonisation, energy performance, and long-term asset strategy. Our team of over 550 surveyors, consultants, and advisers works across every type of commercial property, helping owners, landlords, and investors make decisions that protect and grow the value of their assets.
We combine thorough technical knowledge of building fabric and systems with a practical understanding of the commercial pressures our clients face. Whether you are looking to understand your current exposure to heat wave building risk, planning a programme of improvement works, or seeking to improve your EPC rating ahead of tightening regulations, we can help.
Speak to BTG Eddisons about future-proofing your buildings
With more than 180 years of experience in the property sector, a proven track record of successful outcomes, and consistently positive reviews from clients, we build plans around your specific assets and objectives.
To speak with a member of our decarbonisation team, call 0330 191 8107, email [email protected], or complete the contact form on our website to arrange a consultation.
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