More Efficient Tomorrow: the DPE on the verge of earning its stripes

Although the Minister of Housing acknowledges that "the overwhelming majority" do their job "competently and impartially", she has nevertheless just announced that checks on diagnosticians will be quadrupled[1]... Or how an entire profession pays for a few unscrupulous practitioners.

A little reminder for those who are agnostic about diagnosis

The DPE is a rating tool that evaluates the energy performance of buildings. When it is criticized, for example, for the discrepancy between its estimate and actual bills, we misunderstand both its ambitions and its means. First, because it is not intended to predict actual consumption, but to guide the implementation of renovation measures to move towards greater energy efficiency. Second, because it evaluates the intrinsic performance of a home, that is, independently of its use, for a simple reason: consumption habits vary from one person to another.

In fact, the DPE has been reformed several times to correct its flaws and improve its accuracy. The current version, which came into effect in 2021, is based on stricter criteria and better-defined calculation methods, in particular the 3CL standard (for Calculation of Conventional Housing Consumption), which removes consumption bills from the calculation in order to eliminate a bias that impacted the score. The continuous updating of these methods and benchmarks aims to make the DPE even more reliable. However, critics rarely take these developments into account, as if this evaluation system must constantly improve and prove its objectivity, or even its safety. But what exactly are we criticizing it for?

Peaks and threshold effects

Since the DPE ratings have become binding for owners of thermal sieves (labels F and G), some of them, wanting to rent their property without going through the renovation process or to sell it at a better price, would arrange with the diagnostician to upgrade the accommodation. Suspicious peaks in the energy thresholds on all the DPEs carried out, in particular before the famous letters F and G, would be sufficient proof of this... From there to conclude that these peaks are necessarily the result of "complacent" DPEs, and therefore fraudulent practices, there is only one step, which some have not hesitated to take.

Fortunately, several studies have come to refute the thesis of widespread fraud[2] and shed welcome light on the various causes of the peaks observed at the class thresholds, such as the methodology or statistical law used, the effect of targeted renovations or even standardized construction methods (similar consumption of housing built under the same thermal regulations). Much ado about nothing, or so little: if complacent practices exist, as in any evaluation system (technical inspection, baccalaureate grades, etc.), the diagnosticians would be rather (very) good students.

Remarkable progress, soon to be noticed?

A recent study by the Economic Analysis Council (CAE)[3] shows how the reform aimed at making DPEs more reliable has borne fruit and reduced the proportion of manipulated assessments to a minimum: before 2021, 3,9% of diagnoses were suspect and were in a more favourable category; after the reform, which also made DPEs enforceable, thus engaging the legal liability of owners and diagnosticians, the proportion of diagnoses suspected of being manipulated at the thresholds fell to 1,7%. Can we do better? Undoubtedly, but it seems to me that with more than 98% of well-conducted assessments, we can avoid questioning the ethics and integrity of an entire profession.

Often criticized due to the actions of an unscrupulous minority, the diagnosticians sector deserves a fairer assessment of its work and the progress made: the faults it is accused of have been corrected; the sector has quickly become more professional and everything is being done to force the "complacent" to the expected rigor (strengthening of controls, harmonization of examinations for training organizations and mandatory attendance, digitalization of the DPE course, etc.). In short, diagnosticians are today better trained, better supported, better equipped and better supervised: let us hope that they will be better regarded tomorrow.

[1] https://www.ecologie.gouv.fr/sites/default/files/documents/19.03.2025_DP_DPE.pdf

[2] See in particular the CAE Focus of June 2024, entitled “The effects of DPE reforms on its reliability” (www.cae-eco.fr/staticfiles/pdf/focus-105-fiabilite-dpe-240619.pdf), and the study by mathematician Antoine Le Calvez, which dates from January 2025 (https://alc.io/fr/posts/2025-01-04-analyse-dpe-complaisance/).

[3] https://www.cae-eco.fr/staticfiles/pdf/focus-105-fiabilite-dpe-240619.pdf

Tribune by Mickaël Cabrol, founding CEO of Enersweet (LinkedIn).