What Britain’s air-con row tells us about fighting climate change

Britain is grappling with a rapidly changing climate, marked by increasingly intense and frequent heatwaves that expose a critical vulnerability in its infrastructure and policy. The "urban heat island" (UHI) effect stands as a stark manifestation of this challenge, pushing night-time temperatures in urban centers up to 7C higher than the surrounding countryside. This phenomenon, where concrete, asphalt, and building materials absorb and retain solar radiation, then slowly release it through the night, is at its most dangerous in the early hours when human bodies desperately need cooler air for recovery. Research from the University of Birmingham, modeling a previous West Midlands heatwave, reached the bleak conclusion that the UHI impact alone accounted for approximately half of the 130 heat-related deaths. The human cost of this retained warmth is undeniable and growing.

Jo Shields, head of sustainability for Walsall Housing Group (whg), which manages 23,000 homes across Walsall and the Midlands, regularly encounters this issue. "The heat gain stays within the concrete or the brick," she explains, "so the night-time cooling becomes harder." Last summer, as the region endured scorching temperatures, residents of Ellum Pointe – a whg housing scheme for over-55s – reported that they simply could not cool their flats. The response was immediate and improvised: "We took the community room, closed all the windows and doors, and we put a mobile air-conditioning unit in there," Shields recounts. "And basically, we created an internal cool room." She draws a poignant parallel to the "warm spaces" established during the pandemic for those struggling to afford heating, highlighting the ironic reversal of needs.

Shields’ role, once primarily focused on decarbonisation – reducing carbon emissions from housing stock – has profoundly shifted. She now faces the complex task of balancing these long-term climate mitigation pressures with the immediate, urgent need to adapt homes to rising heat. This dilemma is not unique to whg; landlords across the country are confronting similar, difficult choices. As Britain prepares for a new kind of summer, characterized by homes designed to trap warmth and intensifying heatwaves, two fundamental questions loom large: should the nation embrace mechanical air conditioning despite its significant costs and environmental consequences, and how much should be invested in adapting existing homes versus continuing to prioritize carbon reduction?

The waters are further muddied by an underlying economic and legal paradox: carbon cutting, or mitigation, has historically been far more "investable." Technologies like heat pumps and electric vehicles can be manufactured, marketed, and sold, generating bankable returns. Conversely, spending on adaptation measures such as improved shading, enhanced natural ventilation, and cooler hospitals and homes, while crucial for long-term climate resilience and cost reduction, yields little in the way of immediate financial profit.

Baroness Brown, also known as engineer Julia King, who chairs the adaptation committee of the government’s Climate Change Committee (CCC), argues that this imbalance is deeply embedded in UK law. Under the seminal Climate Change Act, the mitigation half of her committee recommends legally binding carbon budgets that ministers are mandated to deliver and are assessed on annually. Adaptation, however, lacks such statutory teeth. The government is merely required to write its own risk assessments and formulate its own plans. "Essentially, the government writes an essay," Baroness Brown states, "and our job is to say, is it doing the things it said it would do in its essay. It’s not actually to say, are these things any good." Her committee, she reveals, has spent "almost 20 years pulling our hair out" over this disparity. This year, however, has marked a pivotal shift. With exquisite timing, the CCC published a critical report in May, coinciding with Britain’s first heatwave, urgently calling on lawmakers to establish hard, legally binding adaptation targets. The report’s modeling suggests a tangible impact: "We’ve actually looked at the difference that providing some sort of support with cooling for the 30% of most vulnerable homes, and cooling in our hospitals, [with] preventive care visits. The modelling we’ve done suggests that that would reduce 40% of the increase in heat-related deaths that are predicted for 2050." Baroness Brown emphasizes, "We’re saying these are the actions that can make a big difference."

One of the most controversial proposals within the CCC’s report concerns air conditioning. Currently, only about 5% of English homes possess a cooling unit. The Committee now recommends fitting these devices in hospitals and care homes within 10 years, and in schools within 25 years. This recommendation represents a significant departure from years of established government advice, which consistently promoted passive cooling methods – utilizing shade, ventilation, green roofs, and other architectural design features to naturally reduce temperatures – over mechanical means.

Professor Mat Santamouris from the University of New South Wales, widely recognized as the world’s most-cited researcher on urban overheating, remains a staunch advocate for passive approaches. He argues vehemently that machines should always be the last line of defense. His studies demonstrate the profound effectiveness of passive strategies: reflective roofing alone, for instance, has been shown to reduce indoor temperatures from approximately 43C to around 30C, while a simple ceiling fan can provide significant comfort for a mere fraction of the cost of an AC unit. Santamouris is scathing in his critique of contemporary urban planning, lambasting the construction of "unshaded glass towers in cities" as "crazy." His overarching philosophy is clear: "We cannot air-condition our way out of climate change." He also points an accusing finger at the "extremely powerful" air conditioning industry for driving demand, while simultaneously highlighting that passive cooling methods, far from being economically inert, also stimulate economic growth by creating jobs for plumbers, builders, and landscape architects.

Against this expert consensus stand those who contend that Britain’s long-standing hostility towards mechanical cooling has curdled into a form of societal masochism. David Lawrence, from the Centre for British Progress think tank, puts it plainly: "We don’t tell people to insulate their homes in winter and then skip the radiators. So why insist shade and shutters are enough in summer?" He points out the apparent inconsistency that air conditioning is now standard in offices, hotels, and shops, "but we don’t expect it for schools and hospitals – which is kind of odd, because those are places where millions of people are every day," and where heat has a measurable detrimental impact on concentration, learning, and health.

This dispute over the pros and cons of air conditioning is rapidly becoming a political hot potato. Some London councils, adhering to a planning "cooling hierarchy" that prioritizes low-energy cooling methods, have in a small number of cases even ordered property owners to remove air conditioning units. The Conservative front bench has derided such policies as "dark ages" miserabilism, while other MPs and political commentators are demanding an "air-con revolution."

The policy landscape reveals a hesitant, almost covert, acknowledgement of the need for cooling. Since April, the Boiler Upgrade Scheme in England and Wales has offered a £2,500 grant towards a reversible air-to-air heat pump – a machine capable of warming a home in winter and cooling it in summer. It is, in all but name, Britain’s first air-conditioning subsidy. However, it is deliberately badged as a "heat pump" and offers only a third of the £7,500 grant available for heating-only models. The grant’s silence has been deafening; in its first month, only around 45 households claimed it, a stark contrast to the thousands who applied for heating-only models. In Scotland, homeowners can also receive a £7,500 grant for a heat pump via its Home Energy scheme, but critically, there is no funding whatsoever for air-to-air versions that could provide cooling. Northern Ireland offers no universal heat pump grant for households. Furthermore, the terms of the England and Wales scheme exclude social housing and newbuilds, effectively shutting out many of the most exposed and vulnerable populations. This exclusion hits hard in places like Woolwich, south-east London, where a resident named Keisha describes her top-floor flat reaching an unbearable 43C during a heatwave. She calls her building "inhumane"; she and around twenty neighbors in Canada Court and Clifton Lodge are now taking their landlord, the housing association PA Housing, to court over homes they assert are unfit for habitation.

Beneath this financial unfairness lies a cruel physics. Air conditioning does not destroy heat; it merely moves it – out of the flat and into the street. Santamouris’s studies in Sydney show that this expelled heat warms the air for neighbours and drives up the demand for even more cooling by about a third. The machines keeping the financially comfortable cool effectively make everyone else’s nights worse, creating a deepening thermal divide, street by street. This escalating demand also lands on the electricity grid at the worst possible moment: cooling demand peaks on still, hot evenings, precisely when wind generation drops and solar power fades, leaving gas-fired power plants to supply the extra energy. This reliance on fossil fuels generates further greenhouse gas emissions, adding bit by bit to the very climate change effect that is driving the demand for air conditioning in the first place. The irony is compounded by the fact that the same heat driving demand also weakens supply: gas turbines lose output as the ambient air warms, leading to several UK plants having to be throttled back in June.

Despite the expert warnings and the systemic challenges, people are voting with their wallets; demand for portable air conditioning units is through the roof, irrespective of grants or environmental concerns. The evidence from climate experts is clear: Britain should not go down this road of widespread, unmitigated mechanical cooling.

Santamouris and Baroness Brown converge on the same urgent answer: passive cooling first, mechanical machines only where genuinely needed, powered by clean energy, and a clear lesson learned from France’s painful experience in the deadly 2003 heatwave – the vulnerable must be protected, not left to improvise. Cooling every home by machine would place an intolerable strain on the national grid and significantly warm urban streets, directly hampering the collective effort to slow the warming that fuels the demand. Santamouris illustrates this grim future with the example of Tokyo, where so many air conditioners now pump waste heat into the atmosphere that the exhaust alone generates heat equivalent to nearly a thousand watts per square meter – as much energy as falls from the sky at midday. "It’s another sun," he emphasizes, "another sun." While he notes it’s "not the same in London," he warns, "But if we continue in the same way, in some years we will have the same results." The relentless heat of the past two summers, and the high probability of its repetition, deeply upsets Jo Shields. "It’s our survival," she states. Most days, she tries to bury the thought of it, "because otherwise it terrifies me." Meanwhile, Mandy, a resident of Ellum Pointe, expresses gratitude that the new community room with its air conditioning provides immediate respite for her and her mum. "We sit there all day with it on, it helps so much I want one in my flat." Her desire, while understandable, encapsulates the complex, personal challenge at the heart of Britain’s air-con row.