Britain is melting in heat like a blanket that wraps itself thickly around us day and night. For those without air conditioning – which, in summer 2026, is still most of the population – it’s become a relief to step into a mechanically cooled office or supermarket.

But why, in an age of rising temperatures and ferocious heatwaves, do so many of us still lack air con at home? Why are schools closing due to inadequate cooling, and hospitals often struggling on without it?

Estimates for the proportion of UK homes with air con vary from three per cent to 19 per cent – the higher figure coming from 2022 research by the University of East London (UEL). Either way, it’s still not the norm, despite the scorching trajectory we’re on. By comparison, some 25 per cent of French homes have air conditioning, while more than 40 per cent in Spain are fitted with the technology. In the United States, nine in 10 homes have a unit.

Most schools are understood to lack air con, while about 90 per cent of NHS buildings in England are vulnerable to overheating, according to the UK Health Alliance on Climate Change.

The reason Britain is lagging behind, critics of the Government say, is because current policy actively discourages the installation and use of units amid concerns they use a lot of electricity. Indeed, shadow energy secretary Claire Coutinho has suggested that the country’s resilience to hot weather is being damaged by Energy Secretary Ed Miliband’s dogged pursuit of net zero goals (which, in turn, are designed to combat the climate change that has brought these soaring temperatures in the first place).

“The fact that we are one of the only major economies on Earth which has decided that the solution to hot days is to ‘sweat it out’ tells you everything you need to know about our warped energy ideology,” Coutinho wrote in this newspaper last month.

In particular, Coutinho and others have pinned the blame for our lack of domestic air con on building regulations, which discourage its installation in new builds. Dating back to Robert Jenrick’s stint as Conservative housing secretary (before he defected to Reform), the rules on overheating say new buildings should use “passive” means of cooling “as far as reasonably practicable”.

Mechanical cooling methods, like air con, can be installed only if it’s been demonstrated that alternatives have been used first. These passive alternatives might include openable windows, shading to reduce the sun warming through windows, or insulating walls.

In other words, say critics, various hoops must be jumped through before air con is allowed to become the solution. Yet, in temperatures like those we’re seeing this week, passive cooling often simply won’t cut it.

“Britain is getting hotter, yet new builds are not being built with new, higher temperatures in mind,” says Sam Dumitriu, head of policy at Britain Remade. “Part of the problem is a set of building regulations known as Part O. They’re meant to deal with this exact problem, overheating, but for costs and, crucially, environmental reasons, they heavily discourage the use of mechanical ventilation or air conditioning.”

For those who want to install air con themselves at home, there is nothing stopping someone from purchasing a portable unit, but councils have differing policies on the full installation of a domestic unit. “It won’t always be permitted development in every council,” Dumitriu says. “If you want to have a big unit on the outside [of your house], some councils will be very strict on this and some are likely to be more relaxed.”

In some instances, private homeowners are even being forced to tear air conditioning units out of their properties despite the soaring temperatures, with council planning officers citing fears they produce too much carbon dioxide.

The issue is particularly acute in London, where Mayor Sadiq Khan’s 2021 plan for the capital states that use of air conditioning is “not desirable”. It adds that new developments should be designed to “avoid the need [for units] … as much as possible,” given they have “significant energy requirements” and expel hot air, making surrounding areas even more stifling during periods of hot weather.

Some local authority plans go further still, such as the one put together by Camden council, which says it will actively “discourage the use of air conditioning” over concerns it increases “demand for energy” and makes “the local micro-climate hotter”.

Government guidelines on ventilation and thermal comfort in schools meanwhile talk about removing or reducing the need for air conditioning, which makes sense insofar as air con can be financially and environmentally costly – not only because of its high energy usage but because of the greenhouse gases, known as hydrofluorocarbons, often used in it. The guidelines arguably make less sense once the lack of air con becomes so big a problem during extreme heat that schools end up cutting their hours or closing, as more than 1,000 have done this week.

School leaders complain that their buildings have not been designed to keep people cool, and that funding for upgrading them to do so has been lacking.

“Many school buildings are relatively old and were constructed at a time when air conditioning was not widespread in the way that it is now,” says Julia Harnden, deputy director of policy at the Association of School and College Leaders. “In fact, it is more likely that these buildings were designed with cold winters in mind rather than hot summers. This has been compounded by the fact that over the past 15 years or so there has been a big shortfall in government funding for the upkeep and modernisation of the school estate.”

At many schools, there is little that can currently be done to ventilate them beyond opening and closing windows. In some of the newer, Tony Blair-era private finance initiative schools “you can’t even do that,” Tim Fulford, a teacher and National Education Union representative, told the i Paper. Our buildings, both private and public, have often not been designed to cope with today’s temperatures.

“The climate has changed and now active mechanical cooling – maybe not air con but some form of cooling – is probably necessary rather than the last port of call,” says Dr Joel Callow, founding director of Beyond Carbon, a company that helps create sustainable buildings.

“We think correctly designed and installed appropriate low energy cooling systems are a necessity for keeping people safe in the UK from now on.”

Green experts stress that there is no ban or de facto ban on air con in new buildings, despite allegations to the contrary, but the issue is fast becoming a political flashpoint, including on the Left.

The Conservatives have pledged to rip up existing rules, arguing they leave people “suffering unnecessarily” in hot weather. “Why would we limit access to a technology that is proven to save lives, boost productivity and make people more comfortable?” Coutinho wrote last month.

“Energy policy should serve the needs of the British public not the other way around. That’s why we would axe these outdated building regulations which are blocking air con and build an energy system which puts consumers first.”

And even the Climate Change Committee (CCC) is among those now calling on the Government to invest in active cooling – including air con – in care homes, schools and hospitals.

“Heat is the deadliest single climate-related health threat in the UK,” says a spokesman. “By 2050, heatwave temperatures would regularly exceed 40C in large parts of the UK – and the hottest ones could peak at 43C or higher. This could lead to an additional 10,000 heat-related deaths each year without additional adaptation.”

By 2050, the CCC warns, some 92 per cent of homes could overheat. “The intensity and duration of future heatwaves mean we need to plan for more active cooling, such as air conditioning.”

We are in new territory now, and struggling to catch up with the reality of intense heat in a country not previously known for its balmy climes. Much of our housing stock is old, and so too are many of our public buildings – some of our hospitals date back to Victorian times. If we lag far behind other countries in our air con coverage, it’s not just because of current policy, but also that historically, we have hardly needed it, say experts.

The expense is another major factor. In our hospitals, “if it’s a brand new building, it might [have air con],” says Chris Naylor, senior fellow at the King’s Fund. “But a lot of the old ones don’t. It’s partly a financing issue. Since the squeeze on NHS budgets started to kick in from 2010 onwards, successive governments have raided the capital budget to prop up day-to-day services. As a result, the NHS hasn’t been investing in the upkeep of its buildings, and a backlog of maintenance work has built up.”

Some £16bn of maintenance work is needed in hospitals currently, he says. “Air conditioning would have to be paid for out of that limited pot of money.” There are also practical constraints on installing it in older buildings, he adds, while in some urban locations, limited grid capacity could be an obstacle.

Again, this will have to change. Research has found that uncomfortably hot temperatures in hospitals have an adverse impact on patient outcomes and the ability of staff to perform at their best, Naylor points out. During the 2022 heatwave, almost a fifth of UK hospitals were forced to cancel operations. “I think the NHS is starting to wake up to the threat climate change poses to its services and patients and staff,” Naylor says.

At home, we are waking up to how inadequate our houses are for keeping us cool when the mercury soars.

“We didn’t have this kind of demand for residential air con [in the past] and most of our homes are designed to retain heat,” says Dr Mehri Khosravi, energy and carbon senior research fellow at UEL’s Sustainability Research Institute.

UEL research from 2023 found that cost, rather than environmental concerns, was the main reason people cited for not having air con at home. More than half of respondents said expense was the biggest factor in their decision, while 20 per cent cited the environmental impact. It was not surprising, said Dr Khosravi, that Londoners were found to be the most likely to have air con in their homes (30 per cent), “because air con use is about affordability.”

Weather such as we’re currently sweltering in “is a really new climate for the UK,” and public buildings too are “not ready for 35C in June,” she says. We are still in a national mindset of preparing to enjoy the sun when it shines, instead of thinking we need to take action to protect ourselves from the heat, Dr Khosravi argues. “We need to mentally, culturally get prepared,” she says.

But she believes air con should be the last resort “because our national grid is not ready for the pressures of cooling demand”.

And not everyone agrees that the net zero rules are the problem. In the building trade, there’s a view among some that green regulations have, in some ways, helped rather than hindered the cooling of our homes.

“New builds are much better placed than existing homes to cope with any increase in temperature, as a result of the thermal changes made to the fabric of the building,” says Steve Turner, executive director of the Home Builders Federation.

The requirement for greater insulation and thermal efficiency keeps buildings warmer in winter, but also prevents them heating up to the same extent that older buildings might in summer, he explains.

New residential buildings, including care homes, must now be designed to minimise unwanted heat from the sun and allow windows to be open when it’s cooler outside than inside.

Dumitriu, however, believes our building regulations have taken the wrong approach. Solar power has helped Britain’s grid become greener, but by 2030, he says, “we’re going to be in an absurd situation where air conditioning has been discouraged due to its impact on energy use, but we actually have more solar power on the grid than we know what to do with”. We could, nonsensically, end up exporting it rather than using it to power our own air con, he suggests.

We could alternatively use air-to-air heat pumps, which don’t just keep your home warm in the winter but keep it cool in the summer too, he and others argue.

In other words, air con itself doesn’t have to be inherently incompatible with the switch to greener technologies. Last year, the Government announced it was expanding the heat pump subsidy scheme to include air-to-air ones, which can be used for cooling. This represents the first time air con units have been eligible for government funding.

“Air conditioning can be installed in existing and new homes, and we encourage those who want to install it to do so,” says a Government spokesman.

The Government is reviewing planning regulations for new homes to ensure they are effective and proportionate, while the Department for Education’s new construction framework requires ground source heat pumps to be used to deliver cooling.

But as parents of children now stuck at home, patients in sweltering hospitals, and anyone trying to get to and from work by train will testify, we are far from ready for what we’re experiencing now and what lies ahead.