A building that can regulate its own temperature, the first of its kind in France, is being built in Lyon.
Without relying on air conditioning or heating, the building’s design can guarantee a minimum temperature of 22C in winter and a maximum temperature of 26C in summer.
Construction is in progressNEXITY
Construction is set to finish in early 2026, ready for the new residents to move in. All the flats have already been sold, as part of a new system in France called the bail réel solidaire, designed to help lower-income households become property owners.
“Summers in Lyon are getting hotter and hotter, going up to 40 degrees, so the building is perfect for adapting to the environmental transition we are currently experiencing,” said Frédéric Marchal, 64, joint director of residential property company Nexity, which is carrying out the project.
The concept was created by an Austrian company and relies on “excellent thermal inertia”, he said.
“The idea of this project is to be very low technology. We will offer residents a building capable of keeping in the heat in winter and keeping out the heat in summer, simply through the design of the building.
“Unfortunately, French regulations meant that we had to install mechanical air conditioning, which all new buildings must have, but we implemented all the fundamental elements of the original Austrian project.”
The building is insulated with double brick walls, which are both 60cm thick.
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In each living area, there are sensors which capture the temperature, air quality and the level of humidity of the air. Based on these readings, small flaps located next to windows open to adjust the temperature and make sure there is enough fresh air for the residents.
Though the building works automatically, residents are still free to open their windows if they so wish.
Preview of the completed buildingsA Besson
“The design is supposed to be comfortable but not limiting towards its users. If you want to open all your windows and air your apartment, of course you can. Residents can adjust according to their needs,” said Mr Marchal.
Nexity will monitor the building for three years after residents have moved in to see how it meets their lifestyles and needs and to gather precise performance data.
Two building permits have been issued for properties using the same technique in the Paris region.
