The challenge of renovating swimming pools, an energy gap for communities

In “the top 10 most energy-intensive buildings in the city, three are swimming pools,” explains Laurent Guillemin, deputy mayor of Bordeaux responsible for sobriety in the management of natural resources.

A situation that we find in other cities, elsewhere in France.

According to Guillaume Perrin, director of the ACTEE program, an energy saving certificate program supported by the National Federation of Granting and Governed Communities (FNCCR), swimming pools represent 10 to 25% of a municipality's energy bill.

They are the main sources of energy consumption in metropolises according to Ademe, the government agency dedicated to the ecological transition.

At a time of rising energy costs, it is therefore urgent to renovate an aging pool - 60% of the 4.135 French municipal swimming pools are over 30 years old -, especially those built from the 1950s to the 1980s. are the most poorly insulated.

Give up gas

“We had cheap energy, so we did not invest in sufficiently insulated buildings,” notes Guillaume Perrin.

“Heating the air is what consumes the most energy. We are talking about large volumes, whose ceiling height reaches 5, 6, 8 meters with a lot of humidity and air circulation,” explains Laurent Guillemin .

We must therefore invest in “new virtuous air handling units which are responsible for cooling and dehumidifying, then heating the air,” he adds.

An improvement taken into account in two swimming pools currently under construction in Bordeaux (Grand Parc and Judaaïque).

Another (Stéhelin) should be converted into a Nordic swimming pool, an outdoor pool open all year round, in order to eliminate expenses linked to air heating.

As for gas, until now mainly used by French swimming pools, it is "a carbon-based energy to be abandoned in favor of renewable energies", notes Eric Aufaure, coordinator of the building division at Ademe Nouvelle-Aquitaine.

The Judaica swimming pool will therefore be heated using geothermal energy and that of the Grand Parc will be connected to the urban heating network, powered by geothermal energy and wood.

“If the swimming pool cannot be connected to the urban heat network, it can be heated by wooden boilers,” specifies Eric Aufaure. As is the case in Périgueux and Bergerac, in neighboring Dordogne.

Solar photovoltaics can power building lighting, while solar thermal can heat water for showers.

Colder water

Especially since “the swimming pools built during the Trente Glorieuses have flat roofs, where it is very easy to install solar,” says Guillaume Perrin.

In New Aquitaine, 75 public swimming pools are already equipped with solar thermal, six are heated using geothermal energy and around twenty with wood or via connection to an urban heating network, according to Ademe.

"The overall renovation of a swimming pool can allow 60 to 80% savings on a municipality's energy bill", but "cheap and immediate work" is enough to achieve "30% energy savings", says Guillaume Perrin.

The ACTEE program recommends in particular insulating the pipes and cleaning the air vents of the air handling unit.

After the invasion of Ukraine and the subsequent soaring energy costs, this program also recommended that mayors group together the pool usage times in order to lower the water temperature. of 1,5 degrees, excluding times dedicated to seniors and baby swimmers.

In Bordeaux, this measure, in place since winter 2022, saves 5 to 6% of the energy devoted to heating the pool.

Since 2017, the effort has also been supported by Bordeaux Métropole, an intermunicipality bringing together 28 municipalities. Its 40 million euro swimming pool plan supports the renovation of 6 of the 24 municipal swimming pools in its territory and the construction of 7 new buildings.

To find out everything you need to know about the energy renovation of public swimming pools, dive into this ebook, developed by Hellio experts, downloadable directly via this page: https://www.hellio.com/actualites/conseils/livre-blanc-renovation-energetique-piscines