A stroll down German streets usually reveals plenty of postwar architecture, stucco walls and increasingly, air conditioners sitting on balconies or hanging out of windows.

Most homes in Germany – and in northwest Europe — don’t have AC and haven’t really needed it until heat waves became more frequent in recent years. Now that summer temperatures are scorching, many are finding the most manageable way to cool down is with a portable unit.

“Air conditioning isn’t the solution to our problems, but it’s the only solution we have given the circumstances of sub-optimally designed cities and little shade,” said Marc Evans, a 39-year old IT professional in Frankfurt who bought a portable unit last summer for €899 ($1055.)

Adapting to the new climate reality in Europe can be complicated and expensive. Around half of the European Union’s housing stock was built prior to 1980, according to Eurostat, meaning it’s not easy to retrofit for the ducts and wiring needed for an air conditioning system. And in Germany, more than half of the population rents — a larger share than anywhere else in the bloc — so they often aren’t willing to invest on installing permanent AC or can’t do so without landlord permission.

Even homeowners can run into difficulties: Those living in shared buildings first need to clear adding permanent outdoor units with their owners’ association, but these requests are often shot down over noise or environmental concerns.

So after one of the hottest Junes on record, makers and sellers of portable devices say they’re running low on supplies.

A small survey this month showed 18% of respondents said they owned an air conditioner, up from 13% in 2023, though estimates from Germany’s federal environment agency suggest the share is lower. Two-thirds of air-conditioning users in Germany have single units known as monoblocks, such as window or freestanding machines with an exhaust hose, according to survey respondents.

In the US??,??? nearly 90% of US households are air-conditioned, two thirds of them by central AC or heat pumps.An AC for renters

The problem with the most popular portable alternatives is that they often suck huge amounts of power as they expel heat. “Tenants often have to resort to less effective devices than owners and that can have a noticeable effect on electricity costs,” said Daniel de Graaf, a researcher at the German Environment Agency.

Germans wanting a quick solution now also have the option of buying more efficient portable heat pumps. Midea Group Co., a Chinese appliance manufacturer, says demand for its mobile “PortaSplit” has been high in Germany, particularly given the rapidly growing rental market and persistently high temperatures, according to a spokesperson. The model sold out across many stores at the beginning of the summer, he added, and prices for the devices that remain in stock have fluctuated between €800 and €1,600 according to a comparison website Idealo Internet GmbH.

Toom Baumarkt GmbH, a hardware store chain, has also seen high customer interest in portable air conditioners. “While fast cooling and ease of use are top priorities for many customers, aspects such as energy efficiency and suitability for rental apartments are also becoming increasingly important,” said Daria Ezazi, a company spokesperson.

PortaSplit consists of two units, one that blows cold (or hot) air inside a room, and another one that expels heat outside. A narrow hose connects the two through a cracked window, avoiding the need to drill holes through walls. This design is more efficient than devices without an outdoor unit, though it has a higher upfront price tag.

Evans, whose unit is mounted on a bracket outside his living room window, says it’s made a big difference in how comfortable his attic apartment feels and hasn’t noticeably pushed up his power bill. Other methods for cooling the space have always seemed “suboptimal” and “like trying to go for a walk without shoes,” he says.

The growing AC divide

While German law requires landlords to ensure apartments can reach minimum temperatures in the winter, there are no explicit requirements for the summer.

“It is really the exception for heat to be considered a rental defect,” said Jutta Hartmann of the German Tenants’ Association. “In the current rental market, it is, of course, totally unrealistic to demand heat protection.”

The risk of large numbers of people resorting to off-the-shelf fixes instead of more efficient retrofits is that they could drive up power demand as well as emissions. The environmental impact of the various models “definitely differs,” said de Graaf of the German environment agency.

The institution generally recommends using other methods for cooling, such as opening the windows at night, installing good thermal insulation and sun protection, using fans and turning off unused appliances. In cases where air conditioners are necessary, it suggests using climate-friendly cooling agents and energy-efficient split air conditioners, while turning them on sparingly.

“People don’t want air conditioning; they want a comfortable indoor climate,” de Graaf said. “And there are other ways to achieve that.”