Air Énergie, a company specializing in the implementation of "low energy" thermal envelopes located in Alsace, has just completed the overall renovation work of a house from the 70s located in Sentheim (68) with almost non-existent insulation and excessive consumption of fuel oil: roof insulation, insulation of low floors, insulation of exterior walls, windows, installation of a thermodynamic water heater and double-flow ventilation. The house will be heated with wood with a stove and will consume an average of one log per day. Everything is done only with recyclable materials with low carbon and energy impact, allowing the operation to be offset in less than 2 years of energy savings.
This renovation is an example since it made it possible to switch from label G to A and thus achieve passive performance, validated by the Minergie P label.
In terms of financing, Air Énergie collaborated with its partner Hellio, a specialist in global renovation in the Energy Saving Certificates (CEE) system, which was responsible for obtaining the Coup de Pouce Rénovation aid. efficient. The owners have also benefited from public aid MaPrimeRénov '.
Results: a gain in living comfort, guaranteed energy savings of 91%, or € 4 in energy costs saved per year, and an asset valuation of + 530%!
“This project demonstrates the effectiveness of the global renovation, which is THE solution to drastically reduce its energy bill, increase its comfort and its resilience in the face of rising energy prices. This crowns 2 years of work by our teams in the incubation of these programs. Be careful, however, the instability of financial aid today, and in particular of Energy Saving Certificates, jeopardizes the dynamics desired by the government itself. Without the construction companies and sufficient financial incentives, we will not achieve the global renovation objectives imposed by law and the climate emergency! ", emphasizes Christophe Casta, Hellio global renovation project manager for the residential sector.
A 70s house classified G thermal strainer

Before work, this Sentheim house had a G label, the most unfavorable, both in terms of energy and gas emissions, making it a thermal strainer.
The energy audit will reveal that the main heat loss item is insulation (walls: 48%, roof: 18% and floors 13%).
To orchestrate the renovation of their home, the owners decide to call on the expertise of Air Énergie, both an engineering office (Air Énergie Développement) and a construction company (Air Énergie Artisan), which designs and manages high-performance energy renovations: on average 2 to 3 times more efficient than new and the RT 2012 standard. Since 2014, Air Énergie has supported around one hundred private customers in their overall energy renovation project.
The company is also strongly committed to an environmental approach which aims to show that it is possible to overcome energy dependence and the resulting cost, while improving comfort while respecting the environment. “Air Énergie's approach consists of working as a priority on the airtightness and the insulating envelope of the building, without necessarily installing radiators or underfloor heating. One log per day must be sufficient to heat the whole house, evenly, ”explains Dominique Rudler, manager of Air Énergie.
For the first time in the European Union, the energy renovation of an old house will make it possible to achieve the most demanding passive standard in terms of eco-housing for the climatic zone: the Swiss label Minergie P.
7 workstations to become a certified passive house classified A
Air Énergie's other hallmark is to use only recyclable materials with low carbon and energy impact for insulation. The goal is to achieve several objectives, including energy performance of course, but also autonomy, return on investment, air quality, architectural respect and the sustainability of the building.
On this site, Air Energie also ensured the end-to-end management of the project with craftsmen partners of its network for the realization of the different types of work:
- Insulating the roof from the outside with 400 mm of blown cellulose wadding (R = 9.5 m².K / W),
- Insulation on the underside of the low floor with 200 mm of recycled cotton (R = 5.1 m².K / W),
- Insulating the walls from the outside under plaster with 260 mm of cellulose wadding insulation, 40 mm of wood fiber and a plaster finish (R = 5.1 m².K / W),
- The replacement of joinery by triple glazed windows (Uw = 0.67 W / m².K - Sw = 0.55)
- The installation of a thermodynamic water heater which makes it possible to recover the calories coming from the outside to preheat the water (ETAS = 130% - COP = 3.1),
- Finally, the installation of a double flux ventilation for improved thermal comfort and air quality.
The happy owners of the house in Sentheim benefit from energy autonomy, after only two and a half months of work during which they stayed at home (from September to November 2). The renovation of their house also allows them to divide by 2021 the ecological impact of their home.
Almost a third of the cost of the overall renovation financed through aid for energy renovation
In terms of financing, Air Énergie called on its partner Hellio, a benchmark player in energy management, with whom it collaborates regularly: 11 projects are currently underway.
For the renovation of the Sentheim house, the specialist in global renovation in the Energy Savings Certificates system was responsible for obtaining all EEC aid, in the amount of € 30.300.
Since October 2020, and the appearance of the Coup de Pouce Rénovation performance bonuses, Hellio has been a signatory of the charter and listed as a trusted actor by the Ministry of Ecological Transition.
Hellio also supported Air Énergie in establishing the energy audit, in order to ensure the compliance of the file, according to the criteria of the regulations.
The couple of owners (purple household) also benefited from the public aid MaPrimeRénov 'Rénovation total, in the amount of 7.000 €, with the addition of the colander and BBC outlet bonuses, of 1.000 € each.
Aid for energy renovation has thus made it possible to finance nearly 1/3 of the overall renovation, for a total cost of the site of around 120.000 € (ie around 600 € / m²).
This renovation therefore cost three times less than new, without counting the capital gain estimated at 32% (100.000 € for the geographical area) and the saving in energy costs of 4.530 € per year!