Most British homes do not have air conditioning, not because British people are unusually tolerant of heat, but because the housing system has long assumed that active cooling is unnecessary. For much of the past, that assumption made sense. Britain had long winters, short summers and a housing policy centred on warmth, damp prevention, energy efficiency and lower heating bills. Air conditioning was not a basic feature of the home. It was an optional extra.
Climate is changing that premise. Global warming makes heatwaves more frequent, while urbanisation makes the urban heat island effect more pronounced. Cities such as London, Manchester and Birmingham contain large amounts of concrete, asphalt, glass and dense road networks. They absorb heat during the day and release it slowly at night. A few hot days used to be tolerable. When night-time temperatures stay high for several days, a home without cooling is no longer merely uncomfortable. It becomes a problem for sleep, health and productivity.
The contradiction is that many British homes are designed for winter, not summer. Insulation, double glazing, sealed window frames and higher airtightness are meant to reduce heat loss. In winter, this is an advantage. In summer, it can become a trap. Sunlight brings heat into the home during the day, and walls, floors and furniture store it. By evening, the outside may have cooled, but the inside can still feel like a heat store. New homes can be especially vulnerable because they are more tightly sealed than older buildings. If ventilation, shading and orientation are poorly handled, the very features that save heat in winter can amplify overheating in summer.
England has begun to recognise this problem. Since June 2022, new homes have had to comply with Building Regulations Part O, which deals with overheating risk. Its purpose is to limit unwanted solar gains in summer and ensure that homes have a way to remove excess heat. This shows a policy shift from simply keeping homes warm to dealing with both winter cold and summer overheating. But Part O mainly applies to new housing. It does little for the huge stock of existing homes. Most people still live in properties built around an older climate assumption.
Nor is air conditioning something that can simply be added at will. A portable unit can vent hot air through a window, but it is inefficient, noisy, bulky and often lets warm air leak back in. A proper split air-conditioning system needs an outdoor unit, refrigerant pipes, drainage and electrical connection. Many British homes, especially flats, were never designed with these in mind. There may be no suitable external wall, no balcony space, no clear drainage route, insufficient electrical capacity and leasehold rules that restrict alteration to the outside of the building.
The planning system also limits the possibility of Hong Kong-style room-by-room cooling. An air conditioner is, in technical terms, a form of air source heat pump. It does not create cold air; it moves heat from indoors to outdoors through a refrigerant cycle. If the system can operate in reverse, it can also move heat from outdoors to indoors in winter. This kind of split unit, able to cool and heat, is usually treated in Britain as an air-to-air heat pump. Its installation therefore falls under the rules for air source heat pumps and permitted development.
In England, a qualifying air source heat pump may in some cases be installed under permitted development without a full planning application. But this does not mean unlimited air conditioning. For semi-detached houses, terraced houses and flats, normally only the first air source heat pump can qualify under permitted development. Detached houses may have up to two. The equipment must not be used solely for cooling, and it must meet requirements on certification, size, location, noise and visual impact. In other words, a semi-detached house cannot usually copy the Hong Kong model of putting separate split units in the living room, bedrooms and study simply under permitted development. It may need a planning application, and it may also face limits from external wall space, neighbour noise, conservation rules and property covenants.
Flats are more complicated still. Even where planning rules allow a unit in principle, the resident will usually need consent from the freeholder, managing agent or residents’ management company. The external wall is often a shared or managed part of the building. Noise can affect neighbours. Condensate drainage can create disputes. For renters, the constraint is more direct: without the landlord’s consent, fixed installation is effectively impossible. These rules are not designed specifically to oppose air conditioning. They reflect a housing system that never treated outdoor cooling units as normal domestic infrastructure.
This is the structural difference between British and Hong Kong housing. In Hong Kong, high-density housing has long treated air conditioning as a basic feature. Building façades, window ledges, service platforms, drainage and electricity provision have evolved around that use. British housing works the other way round. The system assumes that a household may add one or two units in exceptional circumstances, not that every room will have independent cooling. When the climate was mild, that saved cost. As hotter summers become longer and more frequent, the lack of provision becomes an expensive bottleneck.
The cost problem follows from this. If new homes were designed from the start with pipe routes, drainage, electrical capacity, external platforms and noise control, the cost could be absorbed into the wider development. Retrofitting after completion is different. It means drilling walls, running cables, finding external locations, seeking permissions and managing noise concerns. Technical feasibility is not the same as economic practicality. The price British households face is not just the price of an air-conditioning unit. It is the accumulated cost of not having reserved the option earlier.
In the short term, the easiest response remains passive cooling. Open windows in the early morning and evening. Close curtains or blinds during the day. Keep direct sunlight out of the home. If a property has good cross-ventilation, these methods can reduce indoor temperature. But they have limits. People living beside busy roads may not be able to keep windows open because of noise, dust and exhaust fumes. Ground-floor residents may worry about security. Pollen, pollution and safety risks also matter. Ventilation is not only a question of window size. It depends on whether people can actually use those windows in real conditions.
Another practical response is to spend the hottest part of the afternoon in air-conditioned places such as supermarkets, shopping centres, libraries, cafés or public buildings. In Hong Kong this sounds ordinary. In Britain it is becoming a form of urban adaptation. When homes cannot be modified quickly, cooled public or commercial spaces become temporary heat shelters.
That solution is much harder for people who work from home. British homes were traditionally understood as places for evening rest, while daytime work happened in offices. After the pandemic, remote work made the home carry an office function as well. If indoor temperatures approach 30℃ for long periods in the afternoon, people do not merely feel uncomfortable. Concentration falls, fatigue rises, video calls become harder, computers run hotter and sleep quality suffers. For older people, young children and those with chronic illness, overheating is not a comfort issue. It is a public health issue.
The air-conditioning question in Britain is therefore not simply whether every household should install a unit immediately. It is whether the housing system can accept that the climate has changed. In the past, the main bottleneck was winter fuel poverty, so the answer was insulation. In future, the bottleneck may increasingly be summer overheating, so the answer cannot simply be thicker insulation. New homes need to allow for shading, ventilation, low-cost future adaptation and active cooling where necessary. Older homes must confront the practical limits of retrofit, planning rules and ownership structures. Air conditioning may still not become as standard in Britain as it is in Hong Kong, but treating British homes as if they will never need cooling is becoming harder to defend.
