Created in 2006, reformed in July 2021, the energy performance diagnosis (DPE) of buildings, with its rating from A, for very energy efficient, to G, for thermal sieve, is seriously called into question by a full-scale test of the National Consumer Institute (INC), published in the June issue of magazine 60 million consumers. The principle is simple: call on four home owners who each use five diagnosticians, then compare the results, under the supervision of an expert. “After two years of consultations which led to the 2021 reform intended to make the ECD more reliable, we expected progress compared to our previous survey in 2018, but this is not the case”, summarize Fanny Guibert, journalist, and Virginie Potiron, lawyer, authors of the article. As for the price of diagnoses, they vary widely, from 110 to 319 euros for the same pavilion in the Paris region, the most expensive not being, moreover, the best.
The same house from before 1948, in the region of Bordeaux, is classified B by a diagnostician, C by two others and D by the last two, the expert awarding, in fine, the note D. The very good note, B , was attributed by a professional who was mistaken about the performance of the heat pump.
The note for a house in Corbeil-Essonnes, built in 1993, recently renovated and equipped with a heat pump, waltzes from C to E, while the expert classifies it as D. Significant errors on the area, which varies from 94 to 120 square meters according to the reports, omissions of partitions, skylights, radiators in the bathroom and erroneous construction dates explain the great divergence of results.
“Problem of training diagnosticians”
“It seems to us that there is a problem with the training of diagnosticians, most having received their approval before the 2021 reform and may not have fully integrated the new calculation method, analyzes Fanny Guibert. They also have to devote time to each dwelling, between an hour and a half and two hours, and go to all the rooms, even cluttered ones, in the cellar, in the attic…” “The owners have every interest, before the visit, in gathering plans and invoices for the works and in checking the data taken into account in the DPE”advises Virginie Potiron.
The Federal Consumers’ Union, UFC-Que Choisir, made the same observation in its January issue, citing the case of a chalet owner who undertook major insulation work, with the installation of 50 centimeters thick in the attic, airtight entrance doors, double glazing, a high-efficiency boiler, dual-flow ventilation, to see the building go from grade D… to grade G The theoretical consumption is fixed, by the diagnostician, at 3,550 liters of fuel oil, and has proved, in use, to be very overestimated since 2,000 liters is enough, but the new calculation method excludes referring to real consumption. .
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