Real estate diagnosticians contest a new study which concludes on upgrades and anomalies in DPEs

Although the Krno study suggests that housing is regularly classified more favourably than it should be, the CDI warns against a simplistic interpretation of the results, and recalls the complexity of the process of producing DPEs.

Fundamental errors in the methodology

According to Thierry Marchand, former president of the CDI, "The Krno survey highlights a flagrant lack of rigor in the analysis of DPEs." Indeed, one of the CDI's main criticisms concerns the histogram presented in the study, which displays "peak effects" in the results. But the legend of this graph mentions a performance scale based solely on the energy consumption of housing, expressed in kWh/m²/year. However, since July 1, 2024, the energy performance class is no longer based solely on energy consumption, but also on greenhouse gas (GHG) emissions.

For Thierry Marchand: "Wanting to make an EPC more precise while omitting essential information like this shows a flagrant lack of rigor. The energy performance class is no longer measured in the same way since July 2024, and it is therefore imperative that studies like that of Krno integrate this new data to be relevant."

A DPE which evolves with a two-part calculation method

The CDI stresses that the DPE remains a useful tool for estimating the energy performance of buildings, although its accuracy is not absolute. "The DPE system is carried out in two modes: either with precise input data, provided by the owner, or in degraded mode, when this information is missing. The latter case can sometimes result in less precise assessments, but this is not a reason to systematically accuse fraud or complacency," recalls the CDI.

This distinction is crucial to understanding the results of Krno's study. Indeed, a property located near class F, whose DPE is based on generic or insufficient information, could appear to be a less efficient home than it actually is. "A homeowner identified at the beginning of the F segment has every interest in waking up and finally providing the supporting documents to produce the most accurate DPE possible," adds Thierry Marchand.

An analysis that ignores crucial DPEs

The CDI also points out that Krno's study is based on a methodology that excludes a large number of recent DPEs, which have been reissued based on legislative and regulatory updates, in accordance with current standards. "These reissued DPEs, which take into account the latest regulatory developments, should not be included in the statistics, because they reflect the reality of current housing. Taking these old diagnoses into account distorts the conclusions of the study."

The DPEs located in the threshold effect zone, particularly around classes F and E, are, according to the CDI, often the closest to reality. "These results are in no way complacent DPEs, quite the contrary. They reflect a standardized methodology and a calculation which, in the majority of cases, remains an estimate of energy performance and not an exact science," specifies Yannick Ainouche, president of the CDI.

A call for rigor for constructive criticism

The CDI recalls that, in order to effectively criticise a system as complex as the DPE, it is essential to adopt a rigorous and methodical approach.

"Criticizing without taking into account recent developments, neglecting crucial contextual elements such as regulatory changes, can only lead to erroneous and unjustified conclusions," says Yannick Ainouche, president of the CDI.

The DPE, like any assessment tool, must be used and interpreted with care. Homeowners, especially those at the beginning of segment F, must be vigilant and provide accurate information to ensure the most accurate diagnosis possible.

"Finally, the CDI reminds us that real estate diagnosticians play a fundamental role in compliance with regulations. Their mission is not to optimize the DPE downwards or upwards, but to provide a reliable diagnosis, based on the available data, and to support owners in implementing a strategy to improve energy performance.", concludes Yannick Ainouche.