A buyer purchases a house rated C on its energy performance certificate (DPE). The following year, the electricity supplier warns her of unusual consumption. It takes a court-ordered expert appraisal, years later, to learn the cause: an insulation defect due to uncertified materials. Is her action under the hidden defects warranty long time-barred, or does it run from the expert’s report? The decision of the Third Civil Chamber of the Cour de cassation (the French supreme court for civil matters) of 8 January 2026 retains the report. It also recalls that, against the surveyor who drew up the certificate, the limit is different and starts earlier.
The facts
By deed of 25 June 2008, sellers sold a dwelling house for €340,000, handing over an energy performance certificate that rated it C. On 29 May 2009 the electricity supplier warned the occupants of an unusual level of consumption; the buyer told her legal-expenses insurer of her difficulties in heating the house.
In September and October 2014 she had a court expert appointed, who filed his report in early 2015: the insulation defect stemmed from a choice of uncertified materials. In July and August 2015 she sued the sellers under the hidden defects warranty (vice caché), and the surveyor with his insurer in tort. On 11 January 2024 the Montpellier Court of Appeal held both actions time-barred: the two-year limit of article 1648 had, it said, run from the 2009 letter.
The decision
The Cour de cassation quashed on the hidden defects warranty and dismissed on the surveyor’s liability (Cass. 3e civ., 8 January 2026, appeal no. 24-12.714).
Against the sellers. Under article 1648, first paragraph, of the French Civil Code, by which the action “must be brought by the buyer within two years of discovery of the defect”, the Court faulted the Court of Appeal for running the limit from 2009 “after having found, first, that the building’s insulation defect, established by the expert and due to a choice of uncertified materials, constituted a hidden defect predating the sale and reducing the use of the property, and second, that the expert’s report had been filed” in 2015 (translated from the French). Discovery of the defect means knowledge of its cause and extent, not the sight of a high bill.
Against the surveyor. The action in tort is time-barred after five years “from the day on which the holder of a right knew or ought to have known the facts enabling him to exercise it” (article 2224). The Court of Appeal found, within its own power, that the buyer had learnt of the house’s “energy-hungry nature” from the 2009 letter, “thereby showing that the error in the energy performance certificate was known to her from that date”. The claim of October 2014 was therefore late, whatever the mistaken reason about the two starting points being the same.
What this changes for the valuation
Two limits, two starting points. Against the seller, two years from discovery of the defect, understood as knowledge of its cause, which often requires an expert appraisal. Against the surveyor, five years from the day the buyer knew or ought to have known that the certificate was wrong, which may be the first abnormal bill. A buyer who waits for the appraisal before bringing everything may therefore save one action and lose the other. A private expert’s note, commissioned at the first signs, allows a claim against the surveyor within the limit, without waiting for the court-ordered appraisal.
What the report quantifies. The hidden defects warranty opens the price-reduction action (action estimatoire), the return of part of the price (article 1644), which the courts measure by the cost of remedial works or by the loss of value, whichever best repairs the defect in use. For an insulation defect, the report brings together three elements: the cost of the insulation works needed to reach the announced performance, the market loss of value between a C-rated house and one of its real rating, established by comparison, and the excess consumption borne since the purchase. Against the surveyor, the recoverable loss is the lost chance to negotiate the price or to walk away, as the Cour de cassation held in 2024 for an incorrect certificate, not the cost of works.
The valuation date. The loss of value is measured at the date of the sale, at the market prices of the time, since it is the price paid that is at issue; the cost of works is measured on the day it is quantified. The report must date each head and explain why, failing which the other side easily obtains a reduction of the amount.
The certificate as evidence. Since the 2021 reform of the DPE, the certificate is binding on the seller, and its rating weighs directly on the price, with letting bans on the worst-rated homes. A wrong certificate is no longer a matter of comfort: the gap between the announced and the real rating is an element of value, which the expert translates into euros with the sale references by energy rating available in the area.
What the expert takes from it
- The two-year limit of the hidden defects warranty runs from knowledge of the cause of the defect, often fixed by the expert’s report.
- The action against the surveyor runs from the first serious warning, not from the appraisal; it is lost sooner.
- A private expert’s note at the first signs allows a timely claim against the surveyor.
- The energy loss of value is measured at the date of the sale, by comparison and by the cost of works; the report dates each head.
- Against the surveyor, a lost chance is quantified; against the seller, a price reduction or works.
Further reading
The Property loss of value page describes the assignment, its timescale and its fee. The glossary entries vice caché, moins-value and valeur verte complement this article. On the same theme: Incorrect energy certificate: lost chance to negotiate the price, Hidden defect repaired by a third party: the price-reduction action remains open and Energy certificate reform 2026 and market value. The decision is available on Légifrance.
What next
Does your house use far more energy than the certificate announced?
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