If DPE is to be made fairer, it is also urgent to reduce the volume of errors in its production. This is what Nicolas Laloum, the founder of Jool, has opted for.
DPE, three letters with great power. Depending on the diagnostic classification of the energy performance of the house, an owner can find himself with a total ban on renting his house or with thousands of euros in renovation work. Significant weight, therefore. However, its reliability stands out more and more. If until now it was real estate professionals who complained about it, now it is a more official organization, namely, the Economic Analysis Council.
The lack of reliability is therefore highlighted Minister of Economy Bruno Le Maire and Prime Minister Gabriel Attal announced that it would be revised and simplified, which should be mid-February. One company, Joole, has taken the lead in planning to become the new benchmark for real estate diagnostics. Founder Nicolas Laloum believes that it is essential to adapt the current method (known as “3CL”) to small areas.
“The latter are disadvantaged for two main reasons. Firstly, the consumption of sanitary hot water (we need approximately the same amount of water for a larger property), but with reduced consumption per square meter, small areas are severely penalized. small areas, surfaces that are lost (walls, ceilings and to simplify the floors that separate the accommodation from the unheated external surface, Editor’s note)/habitable area is much larger. is larger than the smallest area. In fact, if we compare. 15m2 by 30m2, the wall area is approximately the same, and 15m2 The residence for is half as big.
Nicolas Laloum recalled that the primary objective of the DPE is to provide prospective buyers with a good benchmark for comparing real estate performance. However, today, properly insulated and heated 15m2 will always be classified as E, F or G.
“This means that for small areas, we no longer think on a scale from A to G, but from E to G. The same property that is slightly larger and properly insulated can quite easily be classified as C or D. This means that A buyer who sees two detached houses for sale, one 15m2 and the other 30m2, cannot really compare their performance thanks to DPE. We don’t really encounter this problem if we compare an 80m2 house to a 100m2 house.” .
The second objective is, of course, to direct the renovation works. “Here, again, do we want to encourage people to renovate 15 m2 beyond what is reasonable? Or do we prefer to focus on households that consume the most in absolute terms (and not per square meter)?”
It is becoming urgent to change the DPE calculation methodology to make it fairer, but for Nicolas Laloum, regardless of the calculation method, it is necessary above all to reduce the volume of errors when performing the DPE. As evidence, Joole* cites research on the reliability of DPE. In this study, Joola was interested in two input data: the construction period of the house and the type of boiler (when the latter is collective). And it is seen that 20% of the DPEs made in Paris in 2023 have an error in at least one of the two input data analyzed. In 11% of DPEs, the construction period of the building is incorrect. And 21% of the DPE corresponding to properties with a collective boiler involves an error in the type of boiler.
Support for diagnostics
Thus, 60% of defects in boilers are not beneficial to the owners. That is, for these cases, the indicated type of boiler consumes much more than the actual type of boiler. In 62% of cases, defects during the construction period are unfavorable for the owners. This means that the stated construction period is older than the actual construction period.
“In fact, in the modeling used for DPE (the 3CL method), many values depend on the year of construction and the final consumption worsens with the age of the building,” explained Jool in the press release.
Why such mistakes? “The owners are not sufficiently informed and do not provide the requested documents in most cases. On the diagnostic side, the pressure of competition in the real estate diagnostic market often limits the time and resources available to carry out a thorough investigation. Even the latter. should go beyond its legal obligations (the owner completing the lack of documents provided, for example).
That is why Nicolas Laloum decided to create Joole, which is based on two main axes. First, create a diagnostic network. As for individuals, it will make it possible to find a reliable and certified diagnosis, whose prices will not change between 200 and 900 euros for the same service. This will allow diagnoses to trust each other’s expertise when in doubt. The other focus is the recovery of data about the home. Public data but difficult to access because they are scattered. “Currently, when a diagnostic does not have the required data, it leaves a gap. With Jool, a set of data will already be included when the diagnostic arrives at the address where the diagnosis will be made,” explains Nicolas Laloum.
– For the years of construction: Jool has compared the DPE data made in 2023 (available in open data) with the official data of the construction period of the buildings made available by different organizations (the State or APUR).
– For collective boiler data: Jool took the type of boiler most often replaced in the DPEs made after 2021 for each building, the actual boiler type of the building.
From there, Jool compared for each DPE whether the supplied boiler was the one estimated for the building. It should be seen that this method is not exact but it is good, because it systematically underestimates the number of errors: because either the actual boiler type estimated is correct, and a detected error at that moment is a real error. . Or the actual boiler type estimated was incorrect, but this means that the correct boiler is the least represented boiler in the building’s DPE history, so there are even more faults than were actually detected. . In short, when it is said that 21% of collective boilers are defective, it is at least 21%.