1 patent
1 energy-plus, low-carbon certified residential building equipped with the solution

Substantially reduce the energy consumption of domestic hot water and/or heating production.


One of the measures in France’s Energy Transition for Sustainable Growth Act is to “improve the energy and environmental performance of new buildings with the overriding goal of promoting energy-plus buildings starting in 2020.” The legislation also recommends reducing the energy consumption of existing buildings by a third. Is the “recommendation” just another example of greenwashing, or is it a challenge that can be overcome by technology and more environmentally-sustainable user behavior? The Myriade project opted to take the challenge!

When it comes to energy, there is a lot of talk about buildings, and for good reason. In France, buildings alone account for 24% of greenhouse gas emissions and 45.1% of total energy consumption.


Therefore, it is only logical that France’s far-reaching energy-transition legislation contain ambitious objectives for buildings:


Building stakeholders are seeking increasingly innovative, high-performance solutions to help reach these targets without dramatically increasing construction costs.

Project partner France Air has been designing and selling air treatment, HVAC, and domestic hot water systems for nearly 60 years. Very early on, this innovative company turned its attention to solutions operating off of alternative energy sources like solar, gray water (from showers, washing machines, and dishwashers), or extracted air from HVAC systems. France Air initially focused on recommending these solutions, and later decided to innovate by developing a single system combining all of these mature, proven technologies, with the ultimate goal of lowering energy consumption while improving occupant comfort and indoor air quality.

Air and heating industry technical center CETIAT confirmed the benefits (especially in terms of energy) of the idea, positioning France Air to respond to a French energy agency call for projects on the topic of “sustainable buildings by 2020.” The project submitted included completing feasibility studies of a multi-energy, multi-use energy harvesting system for commercial and multi-family residential buildings. The project, called Myriade, was selected and work began in 2016.



Results :



Myriade is now a modular domestic hot water and heating production system for new commercial and multi-family residential buildings. The system’s real-time capabilities allow it to “choose” the building’s three sources of recoverable waste energy (extracted air, gray water, and solar, which can be used separately or together) before resorting to gas or electricity. Another benefit of Myriade is that it is easy to expand with new modules without interrupting operations and to modify in the event of new environmental regulations.

The Waldhorn residential building in an eco-neighborhood in Strasbourg was recently completed. The building is equipped with geothermal heating system that collects heat from the Rhine River’s water table and the Myriade heat harvesting system for extracted air and gray water. The building is has earned energy-plus and low-carbon certifications and won a low-carbon building award from France’s property development federation in 2017.



As soon as the system’s Title V certificate is officially issued, France Air will release Myriade on the market. The system’s very high environmental performance (60% lower than the thresholds in France’s RT 2012 environmental legislation) will be a key selling point. The system can cut the cost of producing a cubic meter of domestic hot water by more than half—a benefit that is sure to win over property developers and subsidized housing operators.

Given the relatively long turnaround times for property development projects, France Air is not expecting the solution to generate any revenue in the short term. However, the company is already actively promoting the solution to the owners of all innovative, high-energy-performance projects (low-carbon, energy-plus, etc.). France Air is also keeping a close eye on local regulations, as local governments increasingly implement more stringent requirements than the national regulations—especially concerning renewable energy—to encourage more sustainable building projects in their communities.