Real estate technical visit: DPE 2026 standards

The energy performance diagnostic has changed in nature. For a long time a simple piece of information given to the buyer or tenant, it has become an enforceable standard whose result determines the right to let a property. An insufficient rating cannot be offset by a price reduction: it prohibits the property from being let. This shift explains why the topic has moved from a technical file to a matter of asset-management strategy.

What the diagnostic measures

The diagnostic assesses the property's primary energy consumption and its greenhouse gas emissions, expressed in kilowatt-hours per square metre per year and in kilograms of carbon dioxide per square metre per year.

The final rating retains the less favourable of the two indicators. A property that performs well on consumption but is heated by a highly emitting energy source will be rated on this second criterion. This rule, known as the double-threshold rule, frequently surprises owners who have carried out insulation work without changing their heating system.

Seven classes, from A to G, result from this. The last two correspond to what are known as energy-guzzling properties, the priority target of successive restrictions.

The calculation method and its limits

The calculation is based on the physical characteristics of the building — insulation, windows and doors, heating system, hot water production, ventilation — rather than on actual billed consumption. This is a fundamental change compared with the previous method, which could rely on utility bills.

Two practical consequences follow. Occupants' behaviour does not influence the result, which makes diagnostics comparable with one another. And a vacant property can be assessed, which was not always the case previously.

The trade-off is the result's sensitivity to the quality of the survey. Doubt about a wall's insulation, the absence of supporting documentation for a window, or a poorly measured surface area can shift the rating by a class. In the absence of proof, the assessor applies default values, which are systematically unfavourable. Providing invoices for work carried out, insulation certificates and equipment specifications is therefore not a courtesy: it is what prevents a penalising rating.

The method has also been adjusted for small floor areas, where the calculation mechanically penalised the rating because of the weight of domestic hot water relative to floor area. An old diagnostic covering a studio flat deserves to be redone under the corrected method: the rating can improve with no work at all.

Enforceability and its effects

The diagnostic is enforceable. A buyer or tenant who finds a significant discrepancy between the announced rating and reality can hold the assessor liable and, depending on the circumstances, the seller or landlord as well.

This enforceability applies to performance data, while work recommendations retain only an indicative value. The distinction matters: it is the rating that carries legal weight, not the costing of the suggested improvements.

Its validity period is ten years, subject to provisions that have shortened the validity of diagnostics drawn up under earlier methods. A diagnostic must be redone after work that substantially changes performance — in either direction, since an unrecorded renovation deprives the property of the benefit of its improvement.

The gradual ban on letting

This is the heaviest effect, and it operates in stages.

Energy-related decency has become a condition for letting a property. The most energy-guzzling properties are excluded first, followed by the next classes according to a timetable set by law. As this timetable has been amended several times, the only reliable approach is to check the rule applicable for the year in question rather than rely on a remembered deadline.

A property that is not decent from an energy standpoint cannot be offered for let, and a tenant already in place can ask the landlord to carry out the necessary work, if need be under court order.

For a landlord, the decision therefore has to be made in advance: carry out the work, sell before the relevant deadline, or change the property's use. These decisions require the deadline to be factored into the property's management, as described in our rental management guide.

The energy audit, distinct from the diagnostic

An energy audit is required in addition to the diagnostic for the sale of certain of the most energy-guzzling properties. It does not replace it: it proposes costed work pathways for reaching higher classes, along with an estimate of expected savings.

Its scope is being widened in stages, targeting successive classes. As with the rental timetable, it must be checked for the current year, and it fits together with the rest of the technical diagnostic file given to the buyer.

Usage scenarios

Purchasing a property to renovate. Request the diagnostic and, if it exists, the audit before making an offer. The rating determines whether the property can be let, and therefore the project's profitability, with the tax implications detailed in our article on real estate taxation.

A property rated right at the edge of a class threshold. Have the survey checked before making any decision. A missing insulation certificate may be enough to shift the result, without any work being necessary.

A studio flat assessed under the old method. Consider a new diagnostic: the correction made to the calculation for small floor areas frequently improves the rating with unchanged characteristics.

Frequently asked questions

What does the rating depend on? On the property's physical characteristics, not on billed consumption. The rating retains the less favourable of the two indicators, primary energy consumption and greenhouse gas emissions.

How long is the diagnostic valid for? Ten years, subject to provisions that have shortened the validity of those drawn up under earlier methods. It must be redone after work that substantially changes performance.

Is the diagnostic enforceable? Yes, for performance data: a significant discrepancy makes the assessor liable, and depending on the circumstances the seller or landlord as well. Work recommendations remain indicative.

Does a poor rating prevent letting? Yes, through successive stages covering increasingly broad classes. As the timetable has changed several times, the rule applicable for the year in question must be checked.

Can a diagnostic be challenged? Yes, by commissioning a counter-assessment. Discrepancies most often stem from default values applied for lack of supporting documents, which can be ruled out by providing invoices for work carried out.

What is the difference with the energy audit? The diagnostic rates the property; the audit proposes costed work pathways. The audit is required in addition to the diagnostic for the sale of certain energy-guzzling properties, without replacing it.

Key takeaways

Three points determine what use can be made of a property. The rating retains the less favourable of the two indicators, which means insulation alone is not enough when the heating system is a high emitter. The result depends heavily on the supporting documents provided, in the absence of which unfavourable default values apply. And the deadline for the letting ban must be checked for the current year, not from memory.

For an owner, the practical consequence is simple: the diagnostic is no longer a document to produce at signing time, it is a piece of management data to be tracked like a contractual deadline.