Why the UK Heatwaves Feel Worse in Brick Homes

The UK is facing a serious heatwave, and the problem is not just the number on the thermometer. It is the combination of humid air, warm nights, brick-built homes and infrastructure designed for a cooler country.

The Met Office has warned that temperatures are expected to climb sharply this week, with the peak currently forecast for Wednesday 24 and Thursday 25 June. Southern England could see temperatures up to 38°C, with very warm overnight conditions and widespread tropical nights, especially in urban areas. Humidity is also a major factor, with dew points forecast around 22°C, making the heat feel much more oppressive than a drier heatwave.

UKHSA has also issued red heat-health alerts for several English regions, including London, the South East, South West, East of England, East Midlands and West Midlands, from 1am on Wednesday 24 June until 11pm on Thursday 25 June. That matters because heat is not only uncomfortable. It is a public health risk, especially when people cannot cool down overnight.

The UK Is Built for Cold, Not Heat

A lot of UK housing was designed around one historic problem: cold winters. Brick walls, cavity walls, loft insulation, double glazing and reduced draughts all make sense when the aim is to keep warmth inside and heating bills down.

The same features become awkward during a heatwave. Many British homes use dense brick or masonry construction. These materials have thermal mass, meaning they absorb heat during the day and release it later. In the right climate, with good shading and proper night-time ventilation, that can help stabilise indoor temperatures. In a humid heatwave with warm nights, it can do the opposite. The home soaks up heat all day, then gives it back after sunset like a smug little storage heater.

This is why bedrooms can feel worse at night than they did in the afternoon. The walls, roof, furniture, floors and mattress have absorbed heat. When the outdoor air does not cool properly, there is nowhere for that stored heat to go.

Humidity Is the Real Villain

Dry heat and humid heat are not the same beast. In dry heat, sweat evaporates more easily, and evaporation is one of the body’s main cooling systems. In humid air, that process slows down. The body sweats, but the sweat does not evaporate efficiently. You feel sticky, heavy and overheated because your natural cooling system has been throttled.

That is why this kind of UK heat can feel so oppressive. It is not just hot. It is close. The air feels loaded. Breathing feels thicker. Sleeping becomes harder. Even mild movement can feel more draining than it should.

Warm nights make the problem worse. Tropical nights, in which temperatures do not fall below 20°C, are concerning because the body needs cooler overnight conditions to recover from daytime heat stress. Without that recovery window, heat builds up in people as well as in buildings.

Brick Homes Can Turn Into Heat Traps

The phrase “UK homes are built to retain heat” is broadly true, but it needs precision. Brick does not magically create heat. It absorbs, stores and releases it. That can be useful in winter and sometimes useful in summer if the home is shaded and flushed with cooler night air. The problem is that many UK homes do not have proper external shading, secure night ventilation, shutters, reflective surfaces or air conditioning.

So the heat gets in through windows, roofs, walls and sun-facing rooms, then lingers. South-facing bedrooms, loft rooms, flats, converted buildings and poorly ventilated homes are especially vulnerable. Once the building fabric heats up, simply opening a window during the hottest part of the day can make things worse by pulling in hotter outdoor air.

The better approach is boring but effective: block sun before it enters, keep curtains or blinds closed on sun-facing windows, ventilate only when outdoor air is cooler, and move air with fans where possible. It is not glamorous. It is survival admin with a plug socket.

The UK Also Has an Infrastructure Problem

Heatwaves hit the UK harder because the country is not fully adapted to them. Roads, railways, schools, hospitals, care homes, workplaces and public transport all face strain when temperatures rise sharply. Rail lines can buckle, road surfaces can soften, older buildings can overheat, and public transport can become miserable or unsafe.

This matters because heat is not only a comfort issue. It is a public health issue. Older people, disabled people, people with chronic illness, babies, outdoor workers, renters, people in flats and people without access to cool spaces are all at higher risk. But during extreme humid heat, even healthy people can be affected.

The danger is cumulative. One hot day is uncomfortable. Several hot days plus humid nights become a system-wide stress test.

Climate Change Has Changed the Baseline

The UK used to treat extreme heat as an exception. That mindset is now outdated. The Met Office has repeatedly warned that hot spells are becoming more frequent and that extreme heat has become more likely and intense in a warming climate.

The housing stock has not caught up. Millions of homes were built for a cooler climate, not for summers where 35°C-plus heat becomes a recurring risk. The answer is not simply to bolt air conditioning onto every wall and pretend the problem is solved. That increases energy demand and can worsen emissions if done badly.

The better long-term answer is proper heat adaptation: external shutters, reflective surfaces, tree cover, shaded streets, better ventilation, cooler roofs, building regulations that take overheating seriously, and retrofit support for existing homes.

The Bottom Line

This heatwave feels severe because it is not just heat. It is humid heat, trapped in brick and masonry homes, held overnight by warm air, intensified by buildings designed for winter, and amplified by infrastructure that still behaves as if British summer is mostly tea, drizzle and optimism.

The UK is not overreacting. It is under-adapted.

Until homes, cities and public systems are redesigned for hotter summers, every major heatwave will expose the same uncomfortable truth: Britain has been very good at keeping heat in. Now it has to learn how to let heat out.

Sources

• Met Office: Extreme Heat Warning extended as temperatures forecast to reach 38°C
• UKHSA: Heat-health alerts dashboard
• Met Office: Amber extreme heat warning issued with heatwave forecast