28 degrees in a modern Minergie apartment—and more and more people are complaining

Here's what it's all about

• Even modern Minergie-certified apartments can get very hot in the summer.
• Those affected report indoor temperatures of over 28 degrees despite consistent ventilation and shading.
• According to the Swiss Builders' Association, Minergie standards alone do not provide protection against summer heat.
• Key factors include, among others, effective shading, suitable building materials, and good nighttime cooling.
• As heat waves become more frequent, the problem is growing in significance. The Builders' Association is therefore calling for better construction solutions and simpler permitting procedures for air conditioning systems.

Summary created with

The sun is blazing; it’s 35 degrees outside, and meadows, trees, and rivers are slowly drying up. The heat is currently a major issue throughout Europe. But it’s not just nature that’s suffering from the heat waves—people are, too. Especially those who live in apartments that get very hot during the day.

This affects not only people living in older buildings, but also an increasing number of residents of Minergie-certified apartments, as the real estate platform “Immoinvest” reports.

"It got as hot as 28.3 degrees in my apartment."

Dani R.* from the canton of Zurich lives in a Minergie-certified apartment and is suffering from the heat. He told blue News: “Ever since the first warm days of spring began, the temperature in my apartment hasn’t dropped below 25 degrees.” Dani lives in an apartment building. His apartment is about six years old. “At first, I was happy because I hoped the temperature in the apartment would stay the same all year round.”

But Dani found that the opposite was true. “With these heat waves, it’s been unbearably hot. It got up to 28.3 degrees in my apartment.” And to the “smart alecks” out there, Dani says: “Sometimes I’d open the windows at 5:30 in the morning, when it was only 23 degrees outside, and then close all the shutters.” Even that didn’t help.

To be able to sleep at all, Dani bought an air conditioner. “I was lucky because my parents still had a portable air conditioner in the basement.” The units had already sold out in stores and online shops by the beginning of summer. “I know it’s not the most eco-friendly way to cool the apartment. But at 28 degrees, I just had to do something,” he says.

Air conditioning can help

For the Swiss Builders’ Association, this is not an isolated case. “High summer temperatures can cause even modern buildings to heat up significantly,” says Johanne Stettler, the association’s media spokesperson. Particularly problematic are large window areas without adequate shading and buildings with low heat storage capacity. “Minergie certification alone therefore does not guarantee sufficient protection against summer heat.”

An air conditioner can help with overheated apartments.

Social Democratic Party

Minergie buildings are fundamentally designed to consume little energy. “Minergie buildings have a well-insulated building envelope and therefore require little energy,” Stettler continues. In the summer, effective shading, a balanced proportion of windows, and sufficient thermal mass—that is, building components designed to store heat—ensure that the heat stays outside for as long as possible.

From the perspective of the Builders’ Association, structural measures are therefore needed above all. ““The priority is on structural solutions such as effective exterior shading, appropriately sized window areas, mineral building materials like concrete and natural stone with high thermal mass, and effective nighttime cooling,” explains the spokesperson. If these measures are not sufficient, active cooling or air conditioning may be necessary.

Comfortable living does not preclude achieving climate goals

The association is not surprised that the problem is getting worse. “The problem is becoming more significant due to climate change.” Buildings today must be designed and modernized in such a way that they can withstand the climatic conditions of the coming decades.

That is why the association also advocates for simpler permitting procedures. “Where structural measures are insufficient, it should be easier to install air conditioning systems,” says Stettler. The Swiss Builders’ Association therefore supports legislative initiatives aimed at eliminating or significantly simplifying municipal permitting procedures.

For the association, modernizing the building stock is therefore doubly important. “The push to modernize the building stock is not only key to achieving climate goals and conserving land resources, but also to creating residential and commercial spaces with ideal indoor temperatures in every season.”

*Name known to the editorial staff

Videos on this topic