MaPrimeRénov': Turning your back on wall insulation is a major mistake

Following the suspension of MaPrimeRénov' Large-scale Renovation during the summer and the tightening of eligibility conditions for its reopening on September 30, it is now the MaPrimeRénov' gesture-based route (financing a single job) which is now subject to new restrictions, taking the sector by surprise.

An implementing decree establishing new rules for MaPrimeRénov' is being submitted this Thursday, September 5, for consultation to the National Housing Council with the aim of rapid adoption before the vote of confidence in the government scheduled for September 8.

This text provides for the exclusion of two categories of work from MaPrimeRénov' Parcours par geste from January 1, 2026: wall insulation and the installation of a biomass boiler.

While abandoning support for the biomass sector is justified by air quality objectives, ending support for wall insulation, one of the most effective measures for reducing heat loss, constitutes a strategic error.

End of support for wall insulation: bad news for household thermal comfort

The end of support for biomass boilers is in line with the 2025 measures, which had already reduced subsidies for wood heating (pellet and log, pellet and log stoves and cookers, inserts and closed fireplaces) by 30%. This measure is understandable because, although low in carbon emissions, wood heating is the leading source of fine particles in France.

On the other hand, wall insulation is one of the most effective ways to reduce heat loss in a home (20 to 25% according to ADEME). Removing its support means depriving households of a simple and affordable way to improve their comfort and reduce their bills.

The government's decision is based in particular on the study by the Data and Statistical Studies Service (SDES) of the Ministry of Regional Planning, published in July 2025, concluding that there is a significant gap between the theoretical energy gains from wall insulation and those actually observed after work (3,3 MWh/year expected compared to 0,7 MWh/year observed in electricity; 3,6 MWh/year compared to 1,7 MWh/year in gas).

But this study has limitations: it only assesses household energy consumption, without taking into account their thermal comfort.

Indeed, after energy renovation work, residents adapt their habits and sometimes consume more: this is the "rebound effect." In reality, they can finally properly heat their homes, which previously consumed too much energy. Their energy consumption can therefore exceed expectations, even if their homes are now much more efficient.

Two positive signals in the energy renovation slump

Despite these restrictions, two positive developments emerge for 2026:

Maintaining support for air-to-water heat pumps confirms a direction that Hello Watt has been advocating for years: favoring the heating method that allows for the greatest savings in consumption. The annual cost of a heat pump is €1.510, compared to €2.130 for a biomass boiler[1]. The heat pump also has the advantage of being 100% electric, thus helping to reduce France's energy dependence on imported gas and oil.
The postponement of the obligation to provide an EPC to January 2027 and the extension of access for thermal sieves (housing with an EPC of G and F) to the system by gesture for the year 2026. A pragmatic measure: owners of thermal sieves will not be forced to go through the major renovation process of MaPrimeRénov', which is longer, more expensive, and very unstable, as its closure during the summer of 2025 showed.

These positive signals, however, remain largely insufficient. Hello Watt advocates for greater consideration of thermal comfort in the evaluation of aid schemes and for greater stability in aid schemes. The government's successive U-turns are disorienting individuals and paralyzing the energy renovation sector. The example of summer 2025 is revealing: first, the announcement of a suspension of the two MaPrimeRénov' programs for the summer period, followed by a U-turn ultimately only concerning overall renovation, then, as the summer progressed, a series of new restrictions unraveled a scheme that was nevertheless essential for households and the sector.

To revive the sector and meet climate objectives, the stability and clarity of MaPrimeRénov' are essential: two conditions that are currently absent, accentuated by political uncertainty.

[1] See Hello Watt study from January 2025.

Illustrative image of the article via Depositphotos.com.