With this summer already shaping up to be one of the UK’s hottest summers on record, Londoners are seriously rethinking their property goals.
Air conditioning is moving from a luxury item to a must-have option for London buyers and tenants. Across Chestertons’ London-wide network, agents are increasingly being asked whether properties already have air conditioning – or whether buyers would be permitted to install it.
The issue is particularly pressing for people viewing top-floor flats, which might be vulnerable to overheating.
After another summer of record-breaking temperatures, buyers are no longer judging a home solely on how much natural light it offers. They are also asking how comfortable it will remain during prolonged periods of extreme heat.
The Climate Change Committee has warned that, without further action, as many as 92% of UK homes could be at risk of overheating by 2050.
There is an obvious irony here: climate change is driving demand for air conditioning, yet conventional systems consume significant amounts of energy and can contribute to carbon emissions.
Overheating is not simply a question of comfort. Top-floor flats can be especially difficult to keep cool because heat rises through a building while roofs and walls absorb energy from the sun throughout the day. That heat can then continue to radiate into the property long after the outside temperature has fallen.
Flats with large areas of unshaded glass, limited cross-ventilation or windows that cannot be opened fully can also trap heat. This is particularly challenging in dense parts of London, where traffic, noise, security concerns and air pollution may make leaving windows open overnight impractical.
Adam Jennings, Head of Residential at Chestertons says: “Top-floor apartments often benefit from fantastic light, views and privacy, so they remain extremely attractive to buyers and tenants.
“However, after several very hot summers, people are becoming much more conscious of how warm these properties can get. We are increasingly being asked about air conditioning, ventilation and whether consent could be obtained to install a cooling system.”
City living compounds the problem. Buildings, roads and pavements absorb and retain heat, leaving temperatures in London considerably higher than in the surrounding countryside, particularly at night.
The consequences are not shared equally. Older people, young children and those with respiratory or cardiovascular conditions are particularly vulnerable. People living in smaller flats or social housing may also have fewer options for adapting their homes.
A report by the BBC highlighted the experiences of residents in top-floor social housing flats who had been unable to cool their homes.
At one housing development, a communal room was converted into a temporary air-conditioned ‘cool room’ to give residents respite during periods of extreme heat.
Similar cooling spaces may become more common, but they also underline a much bigger question: why are so many British homes unable to remain at a safe temperature?
There is currently no requirement for new homes in England to include air conditioning. Part O of the Building Regulations came into force in June 2022. It requires developers to stop new homes from becoming dangerously hot and to provide ways for excess heat to escape.
However, it does not require developers to install air conditioning. Instead, they must first consider measures such as positioning buildings away from direct sunlight, adding external shading, using special glazing and improving natural ventilation.
Part O is sometimes described as a ban on air conditioning, but this is misleading. Air conditioning can still be installed in both new and existing homes. The regulations simply encourage developers to use less energy-intensive ways of keeping homes cool wherever possible.
That approach has sound environmental reasoning behind it. A well-designed home should not need an air-conditioning unit running continuously to remain habitable. The difficulty is that these kinds of measures are rarely sufficient during intense and prolonged heatwaves.
Existing homeowners may also need planning permission, listed-building consent or approval from a freeholder before installing an external unit.
The Conservatives describe these restrictions as a ‘de facto ban’. The Liberal Democrats want cooling systems to become compulsory in new homes and essential public buildings. Either way, consumers are already taking matters into their own hands. The number of UK homes with either fixed or portable air conditioning has reportedly more than doubled to over four million in three years.
Retail figures for June also showed increased demand for air-conditioning units and fans as temperatures rose. Chestertons has seen growing evidence of the same shift within the property market.
Air conditioning is no longer discussed only at the very top end. Prospective buyers and tenants viewing modern apartments and top-floor properties are increasingly asking about existing cooling systems or whether they would be allowed to install one later.
Adam adds: “Air conditioning is moving up buyers’ wish lists. In some modern apartments, particularly at the top end of the market, it is becoming a real selling point.
“Buyers viewing homes without it are increasingly asking whether they could install it themselves - and how much it would cost. That is a significant change in a city where cooling was barely part of the property conversation a few years ago.”
For buyers of leasehold flats, that question should be investigated before an offer is made.
Installing an external unit may require freeholder or managing-agent consent. Planning permission may also be necessary, particularly for flats, listed buildings and properties in conservation areas.
Noise, the appearance of external equipment and its position relative to neighbouring homes can all affect whether permission is granted.
A portable unit may avoid some of those restrictions, but it is generally less efficient and still requires a suitable way to vent hot air outside.
London wants to become a cleaner, lower-carbon city. At the same time, its residents increasingly need protection from heat caused by a changing climate.
Conventional air conditioning consumes electricity, produces emissions when that power is not generated from renewable sources and transfers heat from inside a building to the street outside. At scale, this can intensify the urban heat island effect and place additional pressure on the electricity grid during hot evenings.
Yet leaving vulnerable residents in dangerously overheated homes is not a credible environmental policy.
The answer is unlikely to be air conditioning in every room or an outright rejection of mechanical cooling. It is better-designed buildings, more external shading, appropriate glazing, secure ventilation, green roofs, trees and lighter, more reflective materials – supported by efficient cooling where those measures are not enough.
Reversible air-to-air heat pumps may form part of that solution. These systems can provide heating in winter and cooling in summer and are generally more efficient than traditional portable air-conditioning units.
Since 28 April, eligible homeowners in England and Wales have been able to receive £2,500 towards an air-to-air heat pump through the Boiler Upgrade Scheme. However, social housing and most new-build properties are excluded, potentially leaving some of the residents most vulnerable to overheating unable to benefit.
For those of us who grew up experiencing one too many grey, rainy summers, London’s heat problem might be viewed as more of an opportunity than a challenge. It could also mean less need for costly holidays abroad, and more of a focus on creating a city that is increasingly fit for wild swimming and summer sports.
But the fact remains, when it comes to the property market, our infrastructure needs adapting because London homes have traditionally been designed to retain rather than expel heat.
“We do not expect air conditioning to become standard overnight,” says Adam. “But in the years ahead, it is likely to become a much more common feature of London homes.
“Developers and property owners need to recognise that the ability to stay cool is becoming essential to making a home comfortable and resilient.”