Exclusive study — wave 1
DPE reliability barometer 2026
1 in 9 energy certificates shows at least one major inconsistency
As the French DPE reform takes effect on 1 January 2026, the reliability of the certificate itself remains a blind spot. OneDpe ran 689,279 certificates through its coherence engine: 11.1% show at least one major inconsistency — nearly one in nine.
Figures frozen on · Source: OneDpe.fr
Key figures
- 11,1 %
- at least one major inconsistency
- post-stratified by department and vintage (9.5% raw on the sub-sample)
- 689 279
- certificates analysed
- observable sub-sample: category A, 3CL-2021 method, houses and flats, label present
- 36,9 %
- at least one primary inconsistency
- across all primary families, major ones included
- 14,3 %
- of flats affected
- versus 4.1% of houses — major inconsistency
Infographics
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Methodology
Published in full so anyone can check, replicate or challenge it.
Scope, definition, sources and limits
Scope
689,279 certificates. Observable sub-sample: category A, 3CL-2021 method, houses and flats, label present. Results post-stratified by department and vintage to correct over-representation of certain areas and years. The sub-sample is NOT extrapolated to the whole French housing stock.
What the figure means
A "major inconsistency" is a major-level flag raised by at least one of nine control families (usage breakdown, physical inconsistency, domestic hot water, primary/final energy ratio, consumption vs envelope, label, regulatory insulation, ventilation, geographic coherence). It is a STATISTICAL INCONSISTENCY between declared values — never proven fraud, and never an accusation against an identified assessor.
Sources
- ADEME open database — DPE-Audit Observatory (public data, Open Licence)
- OneDpe coherence engine (proprietary analysis, published method)
Limits — what this study does NOT say
- The study covers an observable sub-sample, not all French certificates: the rates cannot be transposed as-is to the entire stock.
- A detected inconsistency does not mean the final label is wrong: it flags a statistically atypical combination of declared values that warrants checking.
- Efficient labels mechanically trigger more cross-checks: the ranking by label must be read with that caveat.
The data
Major inconsistency rate by energy label
| Label | At least 1 major inconsistency | At least 1 inconsistency (all) | Share of sub-sample |
|---|---|---|---|
| A | 19,7 % | 36,6 % | 1,3 % |
| B | 27,9 % | 60,3 % | 5,0 % |
| C | 15,7 % | 48,4 % | 35,8 % |
| D | 5,4 % | 23,3 % | 30,7 % |
| E | 5,9 % | 27,9 % | 16,6 % |
| F | 4,3 % | 34,4 % | 6,7 % |
| G | 22,2 % | 51,2 % | 4,0 % |
Counter-intuitive and stated as such: the best labels (A, B) and label G concentrate the most major inconsistencies; F the fewest. A dwelling declared highly efficient triggers more coherence checks between consumption, building envelope and usage. This table therefore does NOT say that "energy sieves are the least reliable".
Most frequent inconsistency families
| Family | Certificates affected | Share of sub-sample | Major (share of sub-sample) |
|---|---|---|---|
| Usage breakdown | 105 996 | 15,4 % | 2,9 % |
| Physical inconsistency | 63 421 | 9,2 % | 1,4 % |
| Domestic hot water | 51 786 | 7,5 % | 0,0 % |
| Primary/final energy ratio | 48 306 | 7,0 % | 7,0 % |
| Consumption vs building envelope | 29 894 | 4,3 % | 2,4 % |
| Energy label | 22 427 | 3,3 % | 0,8 % |
| Regulatory insulation | 21 415 | 3,1 % | 2,4 % |
| Ventilation | 16 505 | 2,4 % | 0,0 % |
| Geographic coherence | 3 932 | 0,6 % | 0,6 % |
A single certificate can be affected by several families: column totals exceed the overall rate. ⚠️ This table is expressed in RAW values on the sub-sample (corresponding overall rate: 9.5%), not in post-stratified values like the 11.1% headline figure — the two are therefore not directly comparable.
Quotes
Attributable and ready to publish. For an interview, see the contact below.
« The energy certificate now determines a home's sale price, whether it can be let, and access to renovation grants. Finding that nearly one certificate in nine carries a major inconsistency is no longer a technical detail: it is a concrete financial risk for millions of people. »
« Our goal is not to accuse assessors. It is to give owners a simple way to check their certificate's consistency before selling or letting. And we publish the method so that anyone can redo the calculation and prove us wrong. »
About OneDpe
OneDpe.fr is an independent platform of analysis tools for the French energy performance certificate (DPE). It offers free tools — certificate consistency checks, discount estimation, 3CL simulation, 2026 reform simulation, renovation works estimation — built on the analysis of several million certificates from the ADEME open data, cross-referenced with French property transaction data (DVF). OneDpe is published by RIANN SAS (Paris).
Going further
Journalist? Detailed figures, interviews and custom breakdowns: presse@onedpe.fr — reply within 24 hours.