Energy audit

The regulatory energy audit: an action plan for renovation

The energy audit is an in-depth study of a dwelling’s energy performance that goes considerably further than the energy performance certificate. Where the EPC establishes an overview and a rating, the audit offers a genuine roadmap: it models the building’s thermal behaviour and builds costed, prioritised works scenarios to durably improve comfort and reduce consumption.

This document is aimed at the owners of the least efficient dwellings, often described as thermal sieves, giving them a clear view of the steps to take and the gains expected at each stage of renovation.

What sets the audit apart from the EPC

The EPC informs; the audit guides and plans. The audit details several renovation paths, from a first bundle of works to a high-performance renovation reaching the best energy classes. For each scenario, it estimates the energy savings, the improvement in rating and the logical order of the interventions in order to avoid mistakes and extra costs.

Which properties and sellers are concerned

The regulatory energy audit is mandatory when selling single-ownership dwellings, detached houses and buildings held by a single owner, classified among the most energy-consuming. Since April 2023, it concerns properties rated F or G. The scheme was extended to dwellings rated E in 2025, and an extension to class D is planned by 2034. Dwellings subject to the co-ownership regime do not fall under this sale obligation.

The audit must be given to the buyer from the very first viewing of the property, so that they immediately have a complete view of the works to consider.

What the auditor analyses

• The building envelope: walls, roof, lower floors, joinery and insulation levels.
• The heating, domestic hot water production and ventilation systems.
• Thermal losses and the weak points of the overall structure.
• The characteristics of the dwelling: surface, orientation, year of construction and materials.
• The improvement potential and the technical constraints specific to the property.

How the intervention unfolds

The audit relies on an in-depth technical visit, longer than a simple EPC, during which the professional records numerous data and examines each consumption item. It is useful to gather beforehand the energy bills, the supporting documents for works already carried out and any floor plans of the dwelling. These elements refine the modelling and the relevance of the proposed scenarios.

What the audit report contains

The report presents a detailed overview of the current performance, then at least two works proposals organised in stages. Each scenario indicates an estimate of the cost of the works, the expected energy savings, the gain in energy class and the impact on comfort. The document also directs the owner towards the main available support schemes.

• MaPrimeRénov’, a public grant scaled according to income and the scope of the works.
• The zero-interest eco-loan, to finance renovation without interest.
• Energy savings certificates, known as CEE, paid by energy suppliers.

The validity period of the audit

The energy audit remains valid for several years, allowing the owner to rely on its recommendations over time. However, carrying out major works that change the dwelling’s performance justifies updating it, so that the scenarios remain consistent with the real state of the property.

The consequences of a missing audit

When the audit is required, its absence at the time of listing exposes the seller to a breach of their duty to inform. A buyer poorly informed about the scale of the works to expect may contest the transaction or seek the seller’s liability. Providing a reliable audit from the first viewing therefore secures the sale and establishes a climate of trust.

The price of the energy audit and its factors

The audit is a more thorough service than an EPC, which is reflected in its cost. The rate depends on the surface and configuration of the dwelling, its year of construction, the complexity of its equipment and its location. Using a qualified professional and any coordination with the other diagnostics of the sale also influence the final amount.

Frequently asked questions about the energy audit

Does the energy audit replace the EPC?

No. The two documents coexist: the EPC remains mandatory to place the dwelling on the performance scale, while the audit is added for the properties concerned by offering a detailed works strategy. They are complementary and do not substitute for one another.

Am I obliged to carry out the works proposed in the audit?

No. The audit has an informative and incentive purpose: it enlightens the buyer about the possible renovations, but does not require them to be undertaken. The scenarios serve as a guide to plan a renovation at one’s own pace and to mobilise the appropriate support schemes.

Is my co-owned apartment concerned by this obligation?

The sale audit obligation targets single-ownership dwellings. An apartment falling under the co-ownership regime is not individually subject to it, even though the co-ownership itself may be required to undertake other collective energy-related steps.