Since September 1, 2026, the rules for financing energy renovation have changed. Decree No. 2026-822 of August 25, 2026, removes the funding for isolated ventilation or insulation actions by MaPrimeRénov’. Only a substantial renovation, combining at least two insulation actions and a gain of two energy performance labels (DPE), now qualifies for assistance.
This change alters the way to approach a building air renovation project in 2026, encouraging a comparison of global strategies rather than isolated interventions.
Ventilation and insulation after the September 2026 decree: what assistance still funds
The table below summarizes the situation before and after September 1, 2026, for the main items related to air quality and thermal comfort.
| Work Item | Before September 2026 | Since September 2026 |
|---|---|---|
| Ventilation (simple or double flow VMC) | Fundable as an isolated action | Only in substantial renovation |
| Thermal insulation (walls, roof, floors) | Fundable as an isolated action | Only in substantial renovation |
| Wood/biomass heating | Fundable as an isolated action | Only in substantial renovation |
| Thermodynamic water heater | Fundable as an isolated action | Only in substantial renovation |
| Thermal solar | Fundable as an isolated action | Only in substantial renovation |
The direct consequence: installing a VMC alone no longer triggers any public aid. A homeowner wishing to improve indoor air quality must couple this item with insulation to meet the required threshold of two gained DPE labels.
To compare the available approaches, the building air solutions from foyerluxuria.fr group several configurations combining ventilation, insulation, and bio-sourced materials in a substantial renovation pathway.
DPE and A0 mention: the direct link between building air and energy performance
An order from June 11, 2026, prepares for the overhaul of the energy performance diagnosis on January 1, 2027. The notable new feature is the creation of an A0 mention for homes without fossil energy, awarded to properties already classified A or B that exclusively use electricity, renewable energies, or efficient district heating for heating and hot water.
The future DPE will also more finely distinguish airtightness defects, ventilation operation, and air quality. In other words, a renovated home with effective insulation but faulty ventilation will see its rating penalized.
What this changes for a renovation project in 2026
A diagnosis conducted after January 2027 will evaluate ventilation with a level of detail far superior to that of the current DPE. Anticipating this change by integrating an appropriate building air system (double flow VMC, hygroscopic air inlets) now protects the property’s value in the medium term.
Renovating the envelope without addressing ventilation compromises the future DPE. The two items form an inseparable technical couple in the emerging regulations.
Summer comfort and substantial renovation: the underestimated parameter
RE2020, generalized since May 1, 2026, to all new buildings, imposes a summer comfort threshold measured in degree-hours of discomfort. In renovation, this requirement does not apply directly, but it influences the evaluation criteria for substantial renovation projects funded by MaPrimeRénov’.
Homes located in the southeast quarter of France, exposed to prolonged heatwaves like those of summer 2026, experience overheating that insulation alone does not resolve. Without effective night ventilation or suitable solar protections, a well-insulated home can become a furnace during heatwaves.
- Insulating attics and walls reduces winter heat loss but traps summer heat if ventilation does not compensate.
- A double flow VMC with bypass allows for massive night ventilation in summer without opening windows (noise, security, pollution).
- Bio-sourced materials (wood fiber, cellulose wadding) provide superior thermal inertia compared to synthetic insulators, delaying the rise in indoor temperature by several hours.
- External solar protections (sunshades, shutters) remain the most effective action to limit heat gains before they penetrate the wall.
Bio-sourced materials and thermal inertia
The choice of insulation material has a direct impact on summer comfort. A high-inertia insulator like wood fiber slows the propagation of heat through walls. In contrast, expanded polystyrene, effective in winter, allows summer heat to pass through much more quickly.
Combining a bio-sourced insulator with effective ventilation constitutes the most coherent combination for a substantial renovation project aiming for both DPE gain and year-round comfort.
Building air renovation: balancing overall cost and sequencing of work
The removal of isolated actions requires rethinking the schedule of a project. Starting wall insulation without simultaneously planning ventilation exposes one to two risks: the appearance of condensation in the walls (due to insufficient air renewal) and the impossibility of triggering aid.
- Conducting an energy audit before any quote allows for identifying the combination of actions that meets the threshold of two DPE labels.
- Entrusting the ventilation and insulation lots to certified RGE craftsmen coordinated avoids rework.
- Integrating summer comfort into the specifications from the initial diagnosis reduces the risk of later cost overruns.
A well-sequenced substantial renovation project costs less than a series of isolated actions, even without considering the aid. The coordination between insulation and ventilation eliminates moisture-related pathologies and limits rework.
The regulatory framework of September 2026 is constraining, but it also clarifies priorities. Homeowners who engage in a global building air renovation now have an advantage: their post-work DPE will be assessed according to the strengthened criteria of 2027, with documented ventilation and a coherent thermal envelope. These files will capture the full value of the still available aids.
