What is the average cost per m² of the energy renovation of an apartment classified as a thermal sieve?

What does a thermal strainer apartment look like? What are the costs of the work to be carried out to escape energy poverty? What aid is in effect for 2024? Characteristics of the properties, average energy renovation bill, amount of aid, etc.

Ithaque, the specialist in energy renovation for individuals, draws up a sketch of the thermal sieve apartment and gives an idea of the expenses to be expected to get out of it.

What is the profile of apartments classified F and G?

Can we draw a sketch of an apartment labeled “thermal sieve” in France? To this question, the new study carried out by Ithaca answers in the affirmative. Nearly half (49%) of apartments classified F and G are on the top floor of a residence, an over-representation therefore, the share of housing positioned on the top level of a building being only 31%. The survey also reveals that apartments labeled F and G are mostly heated with electricity (61%, compared to 26% with gas) and, for 42%, located in buildings built before 1948.

Finally, and perhaps above all, the most energy-intensive apartments are often the smallest: 44% of colanders have a surface area of less than 40 m2, even though properties of this size only represent 21% of the apartment stock in France.

The larger the surface area of the property, the lower the renovation costs per m²!

These apartments – which consume between 330 and more than 420 kWh/m²/year[1] – will have to be renovated in order to guarantee their occupants a healthier, more comfortable and sustainable home, while allowing the owners to comply with the regulations regarding rental. As Ithaque points out, it is always preferable to renovate at the scale of the co-ownership but this is not always possible. The study conducted by Ithaca also looked at the costs of energy renovation work. Although variable depending on the type of apartment, the average cost of upgrading is estimated at 742 euros per m². However, we observe that the larger the surface area, the less expensive it is to escape from the status of an energy sieve. If the average budget per m² for an energy renovation is around 955 euros for a studio of less than 20 m², it is estimated at 707 euros for an apartment between 20 and 40 m², and at 512 euros for a surface area greater than 40 m².

MaPrimeRenov': the device not to be missed in 2024

The cost of the work may therefore seem high for an owner. However, several mechanisms exist to cushion the overall bill, and in particular the MaPrimeRénov' aid, which has had a facelift since January 1, 2024. The big winners from the reform are the owners who will opt for the new route accompanied by overall renovation. To be eligible, you must also carry out an energy audit and be monitored by a certified organization "Mon Accompagnateur Rénov'", the work must in particular make it possible to gain at least two DPE classes and the treatment of two insulation stations, while respecting a threshold R of thermal resistance – which impacts the thickness of the insulation to be installed. In fact, the rate of coverage of the work could reach 90% for the most modest incomes, with a ceiling set at 70.000 euros (compared to 35.000 euros until now) for efficient renovations: those which will allow you to gain not two but four classes at the DPE (to move from F to B or from G to C).

The system certainly has its weaknesses. The accumulation of eligibility criteria makes the tool complex to understand, and the need to achieve a thermal resistance R greater than or equal to 3,7 kW/m² seems difficult to compatible with apartments located on an intermediate floor. But given that apartments F or G on the ground or top floor represent 70% of the strainers, the device tackles the bulk of the problem. This is also one of the main lessons of the survey: going against the grain of recent interventions, the study clearly shows that it is more possible and relevant than ever to carry out an ambitious energy renovation of your apartment .