Dalkia recovers heat from Tresorio computer servers to warm water in a building managed by Montluçon Habitat

The pilot project will run until 2023. Objective: the goal is to deliver a clean, competitively priced supply of energy to people living in the 48 homes in the social housing block.

The DigHeat digital boiler, designed by Dalkia and the startup Tresorio, comprises computer servers whose heat is recycled to warm part of the building’s domestic hot water supply. It was installed to enhance the comfort of people living in the 48 homes in the Mage apartment building, which is managed by Montluçon Habitat.

Dalkia will harness the heat from Tresorio’s servers, which is given off as a by-product of its cloud computing services. DigHeat, which contains eight servers, produces an average of 10 kW and has a storage capacity of 1,500 litres, allowing it to hold 87 kW of hot water at 63 °C, enough to provide 139 five-minute showers at 37 °C every day. The technology developed by Dalkia and Tresorio can harness and store the heat from this water and supply clean, competitively priced energy to residents in the Montluçon Habitat building.

The digital boiler contributes to the energy transition by capturing the “waste” heat given off by the servers. The innovation also offers a response to the challenges of digital technology by offering an infrastructure that consumes less energy than conventional data centres while curbing the carbon footprint of data-processing facilities, which are increasingly numerous in the age of Big Data.

“With this pilot project, which is a first for the Allier region, Montluçon Habitat has chosen to innovate by hosting the digital boiler system developed by Dalkia and Tresorio with a focus on using low-carbon energy and unlocking energy savings for residents.”

Roselyne Vavra, Managing Director, Montluçon Habitat

"The DigHeat digital boiler, designed in partnership with French startup Tresorio, is an innovation that is central to the revolution in energy and digital technology. It draws on Dalkia’s expertise in heat recovery to provide Montluçon Habitat with clean, competitively priced energy. The installation has turned the social housing block into a smart building at the heart of the circular economy.”

Jérôme Aguesse, Regional Director, Central Eastern France, Dalkia

“The DigHeat installed in the Mage building will provide a field test for the many improvements we have made to our system over the past few years. The new rollout will give residents an eco-friendly supply of competitively priced hot water and special access to a local cloud service.”

Jonathan Klein, Chairman, Tresorio


of storage capacity, i.e. 139 five-minute showers at 37 °C every day


social housing units