By Philip Ord, UK CEO of Qvantum
With the UK experiencing heatwave after heatwave, the summer of 2026 has already been the hottest on record. By mid-July, the Met Office confirmed that the UK had already recorded more days above 30°C than during the whole of the summer of 1976 and, as temperatures are projected to reach as high as 45°C in the coming decades, overheating is now one of the biggest challenges facing property developers and housing associations.
British homes aren’t designed for prolonged heat, particularly since the government introduced stricter energy-efficiency standards (such as Part L), which mean modern homes are built to be highly insulated and increasingly airtight. While this helps to cut carbon emissions and give residents more comfort in the cold winter months, the unintended consequence is that homes are also becoming better at retaining unwanted heat.
As the climate changes, keeping homes cool is becoming just as important as keeping them warm. The National Housing Federation predicts that around 90% of homes could be at risk of overheating by 2050, while the Climate Change Committee has warned that future housing strategies will increasingly need to combine passive cooling measures with active cooling solutions to maintain comfortable indoor temperatures.
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This shift is already being reflected in regulation. Part O of the Building Regulations requires developers to demonstrate that homes can limit unwanted solar gains and remove excess heat to reduce the risk of overheating. Buildings in dense urban environments, categorised as ‘high risk’, face particularly stringent requirements, due to the impact of the urban heat island effect. The Mayor of London’s recent Heat Ready London report reflects a real urgency for combatting overheating in cities, where the problem is more acute.
Passive cooling remains the first line of defence
So far, developers and housing associations have focused on building design to keep temperatures down. Measures such as external shading, appropriate glazing, and natural ventilation can all play an important role in limiting overheating without increasing energy demand. However, these strategies are becoming increasingly difficult to implement in many modern developments.
In busy urban locations, concerns around noise, air quality and security can make opening windows impractical, particularly overnight when cooling is most effective, and cross ventilation is limited in single-aspect apartments. Highly glazed façades, increasing residential density and constrained development sites further limit the effectiveness of passive cooling alone. For many developments, particularly in cities, maintaining comfortable indoor temperatures will increasingly require some form of active cooling.
Rethinking cooling
The obvious response might be to install air conditioning, but this too comes with challenges. Dedicated air conditioning systems require additional plant, space and maintenance, despite potentially only being used for a relatively small number of days each year.
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They also increase electricity demand during periods when the grid is already under the greatest pressure. As the UK moves towards fully electrified homes, simply adding another standalone system is unlikely to represent the most efficient long-term approach. Instead, the industry has an opportunity to consider heating and cooling as part of a single, integrated strategy for year-round comfort.
An integrated approach to home comfort
Many modern heat pump systems can now provide both low-carbon heating in winter and cooling during the summer months, allowing one system to meet changing seasonal demands rather than requiring separate technologies.
Different heat pump technologies achieve this in different ways. Exhaust air heat pumps can provide active cooling to help reduce indoor temperatures during periods of hot weather. Meanwhile, ground source and water-to-water heat pump systems connected to ambient loop networks can make use of naturally cooler ground temperatures to provide highly efficient passive cooling, reducing the amount of mechanical support required. This becomes particularly valuable in larger residential developments.
Fifth-generation ambient heat networks allow heating and cooling demands to be managed across an entire building rather than within individual apartments. Heat removed from one area can be redistributed elsewhere across the network or rejected into the ground, helping to balance differing heating and cooling requirements between north- and south-facing apartments, communal spaces and other occupied areas.
These networks can also help address issues such as overheating in communal corridors, a common challenge associated with traditional centralised heating systems in tall residential buildings.
Designing homes for tomorrow’s climate
As we prepare for more summers as hot as 2026, new and existing homes across the country will need to perform very differently to how they have in the past. That means, as well as reducing heat loss in winter, they must also be designed to remain comfortable during increasingly frequent periods of extreme heat.
That requires a shift in thinking. Rather than treating heating and cooling as separate challenges, developers should be looking at integrated systems that can deliver year-round thermal comfort while supporting decarbonisation. The climate is changing; the UK’s homes must too.
