Elax Énergie raises €30m to make France's electric water heaters smarter
The Paris company, which says its box cuts water heating electricity use by 20 to 25%, wants to turn millions of tanks into flexible storage for renewable power.
Elax Énergie, a Paris-based start-up that makes a smart box for electric water heaters, has raised €30 million from Noria and Crédit Mutuel Impact, French start-up outlet Maddyness reported on 21 October 2026.
The company plans to use the money to sell directly to households for the first time, through a network of about a hundred tradespeople, and to move into collective heating systems.
How the Elax box works
Founded in 2020 by Thomas Tirtiaux and Samuel Beaussier, Elax Énergie sells a smart box that adjusts a water heater's heating cycles to the household's actual use of hot water. It avoids heating water that is not needed and shifts some heating to other times, without changing daily life for the people living there, Maddyness reports.
According to the company, the technology reduces the electricity used for hot water by 20 to 25 percent. That figure comes from Elax Énergie itself and has not been independently verified by Europreneurs Media.
Built on social housing
So far Elax Énergie has grown mainly by working with social landlords. Maddyness reports that it works with more than 100 of them and claims close to 100,000 equipped homes. Its investor Noria cites more than 85,000 homes equipped across more than 100 landlords. Noria also says Crédit Mutuel Impact joined Elax Énergie's capital in September 2026 through its Fonds Révolution Environnementale et Solidaire.
From landlords to households
The new funding is meant to open a much larger market. Elax Énergie plans to launch Elax Pro, a network of around a hundred tradespeople, including plumbers, electricians and heating engineers, who will offer and install the box directly in private homes. The target is France's roughly 15 million installed water heaters, according to Maddyness. A price for households has not yet been announced.
The company also wants to enter the market for collective boiler rooms. It is developing a system that replaces part of the gas used to produce heat with electricity, and says this could electrify up to 50 percent of heat production in some installations.
Water heaters as thermal batteries
Both new businesses support a bigger idea: using water heaters to absorb swings in renewable power. By shifting when thousands of tanks heat up, Elax Énergie aims to soak up surplus electricity from solar and wind farms. CEO Thomas Tirtiaux told Maddyness that, faced with the volatility of solar and wind, these millions of devices must become dynamic thermal batteries serving renewable energy, and that the company's technology is an affordable solution that can be deployed immediately to give the grid vital flexibility. (Quote translated from French by Europreneurs Media.)
Elax Énergie has about 50 employees and plans to hire 30 more by the end of 2027, mainly in R&D, engineering, operations and business development, Maddyness reports.
What it means for European founders and investors
Elax Énergie is a good example of a climate business that does not depend on building new hardware at scale. Instead, it adds intelligence to equipment that is already installed in millions of homes. That makes deployment cheaper and faster, and it creates two sources of value: lower bills for households and flexibility for the grid.
Grid flexibility is becoming one of the most interesting areas in European energy tech, as more solar and wind power makes supply less predictable. Germany's 1KOMMA5° recently raised money for its Heartbeat AI software, which manages home energy systems. For founders, the lesson is to look at the installed base: the cheapest battery may be one that people already own.
For investors, the round shows French impact funds backing a company with real deployment and a clear route to households. The big test will be whether a network of independent installers can sell to homeowners as effectively as Elax Énergie has sold to social landlords.
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