As Britain reels from Europe’s worst ever heatwave, many households are, for the first time, seriously considering air conditioning. Leftists have often been critical of AC, pointing out that there are cheaper, more ecological ways to combat severe heat. But with decades of underinvestment leaving the UK dismally unprepared to handle further heatwaves, is it time to rethink the progressive position on air con?

Like many new technologies, air conditioning can bring significant benefits but also real harms, contributing to external air temperatures and global emissions. Dogmatically denying these harms, as AC boosters tend to, is unhelpful, but likewise refusing to explore how mechanical air-cooling systems could play a more productive role in progressive climate adaptation is just as blinkered.

Fundamental to any leftwing air-conditioning policy must be efficiency. Currently, air con in Britain is installed incredibly inefficiently, in haphazard, one-off spurts, household-by-household with no economies of scale or strategic vision. Much of the technology is ingenious. But, used in isolation, it can become extremely wasteful. Cooling the air inside a building without also taking steps to stop that air from just heating up again is like trying to run a bath with the plug out.

Many British homes overheat simply because they lack good insulation and outside shading. This week my neighbour, struggling in the heat, hung a sheet outside his window to test whether some external shading might stop his bedroom from overheating. He recorded a 17.8C difference between the internal temperature of his unshaded windows and shaded ones – the equivalent of multiple 400W radiators on full blast. Sure, he could install AC, but without first cooling down his windows he’d be throwing money down the drain. And what happens when his air conditioning unit malfunctions, as many are prone to during prolonged heatwaves?

That said, there are specific situations where installing external awnings, shutters or louvres, as is common in hotter European regions such as southern France and Spain, might still not be enough to bring temperatures down during the hottest peaks of the year. In those cases, using a moderate amount of air conditioning is eminently sensible so long as it is in addition to, rather than a substitute for, lower-emissions cooling methods.

“Individual air-con units are the bottled water of urban cooling,” says Smith Mordak, former CEO of the UK Green Building Council. “What we need instead are the equivalent of mains water solutions: shared, available for all, and transformative for public health.” For Mordak it’s not that air conditioning should never be used, but that its installation should be centred around a mission of increasing public health rather than private luxury.

Public transport, for instance, is the perfect example of good strategic air con use. It’s simply not possible to clamp awnings or thick insulation to the outside of trains or buses, but without reliably comfortable public transit systems, whole cities suffer. Everyone on the left of British politics should be calling for more air con on public transport. The fact that the vast majority of London buses still do not have air-cooling systems while almost all private taxis do is severe misallocation of resources.

Transport is a useful comparison here. Air-conditioning systems are, in many ways, analogous to cars. Deployed well, with appropriate licensing and regulation, and in concert with a variety of other transit forms, cars are brilliant. However, unleashed wholesale without strategic oversight as a one-size-fits-all solution, cars can quickly degrade cities and cause unchecked pollution. Similarly, air con, used strategically, could be emancipatory. It is only if we continue today’s purely market-led AC bonanza, with no serious plan for expanding less energy-intensive cooling measures too, or ensuring cooling is distributed equitably, that the technology will exacerbate inequality and further climate breakdown.

Furthermore, dealing with extreme heat represents a huge engine for new skilled jobs and profitable state enterprise that the left should embrace. The French government holds major stakes in critical industries including energy, transport and communications. As temperatures rise, cooling systems will become just as fundamental to a functioning society as other essential infrastructure. Leftists should seize the opportunity to demand public ownership of the cooling sector, bringing democratic accountability while preventing corporate profiteering at the expense of increasingly desperate consumers.

Licensing, too, has a role to play. There are currently no serious restrictions on where or how air con can be installed, other than who can afford it. Rich households can therefore whack in whatever tech they want and run it as hard as they like without any regard for their neighbours or the climate. At the very least, simple rules should require the implementation of lower-emissions cooling strategies before a building can be granted an air-con permit.

The solution to overheating is not air conditioning because there is no single solution to a problem as knotty as climate adaptation. Instead, we need a mix of many tactics including more tree planting to promote urban cooling, as well as European-style external shading such as awnings and shutters, to insulation upgrades, ambient loop heat networks and more cross-ventilation. Deploying air conditioning on its own would be disastrous, exacerbating the very problem it purports to address. However, alongside other cooling measures, it has a key role to play, and it is unhelpful to pretend otherwise. The progressive position on air conditioning should not be a question of whether or not to use it outright, but where, how and alongside which other infrastructure upgrades will make the most positive impact.

• Phineas Harper is a writer and curator