The DPE conversion factor lowered to 1.7 starting January 2027

The Ministry of the City and Housing published in the Official Journal of the French Republic No. 0198 of August 26, 2026, a decree dated August 19, 2026, which lowers the conversion factor of final energy to primary energy for electricity used in the energy performance certificate (DPE) from 1.9 to 1.7. The text, referenced NOR VLOL2617030A, will enter into force on January 1, 2027, and provides for a digital certification system issued by ADEME to reclassify the labels of the affected dwellings.

This modification is part of the revision of the DPE calculation method, which converts final energy consumption into primary energy to establish the energy label (from A to G) of buildings. The new coefficient, which is more favorable to electricity, mechanically leads to an improvement in the performance class of many electrically heated homes, without challenging the input data of existing diagnostics.

A technical modification of the calculation method

The decree replaces the value “1.9” with the value “1.7” in two reference texts: Annex 3 of the decree of March 31, 2021, and point 2 of Annex 3 of the decree of September 15, 2006. This coefficient is used to convert final energy consumed into primary energy, a decisive step in calculating the DPE label.

Furthermore, the text repeals the decree of August 13, 2025, which had already modified this same conversion factor, in order to unify the regulatory framework applicable as of 2027.

A digital certificate to reclassify dwellings

Valid DPEs may be subject to a document certifying the new label, in accordance with the provisions of Article 1 of the decree. This certificate is limited to drawing the consequences of the modification of the conversion factor and does not challenge the works or the input data of the initial diagnostic.

• It is generated in digital form exclusively by ADEME, on the website of the Observatory of energy performance diagnostics and energy audits.
• It can be downloaded by any person and complies with a model published on the website of the ministry in charge of construction.
• Its validity ends on the expiration date of the DPE from which it is derived.

The same mechanism applies to valid energy audits, which may obtain a certificate reclassifying the labels before and after works for each work proposal.

A framed transitional system

In the absence of a certificate issued under this decree, the DPE initially produced remains valid until its expiration date. When a diagnosis has already been the subject of a certificate in application of previous provisions, it remains valid, with the label resulting from that certificate, until its expiration date.

This flexibility ensures the legal continuity of existing diagnoses while allowing owners to benefit, as of January 1, 2027, from a label reflecting the new conversion coefficient.

A major impact for homeowners

By lowering the conversion factor for electricity, the decree improves the energy class of millions of electricity-heated homes, which may facilitate their rental or sale and reduce the number of “thermal sieves” (passoires thermiques). Homeowners will be able to obtain, free of charge via ADEME, a certificate reclassifying their label without performing a new diagnosis—a concrete lever for the energy renovation of the French residential stock.

Official Reference: Decree of August 19, 2026, modifying the conversion factor of final energy to primary energy for electricity relating to the energy performance diagnosis, NOR VLOL2617030A, published in the Official Journal of the French Republic No. 0198 of August 26, 2026.