Since its reform in 2021, the Energy Performance Diagnostic (EPD) has become a central element of energy renovation policy in France. Its objective is laudable: to encourage owners and lessors to improve the energy performance of their properties, in a context of ecological transition.
But as the gradual ban on the rental of "energy sieves" comes into force, it is essential to question the limits and real impacts of this reform.
Undeniable progress…
The new DPE has corrected some aberrations of the old version, which was sometimes based on unreliable estimates. It is now based on a more homogeneous calculation method and takes into account criteria such as insulation, heating and ventilation. The readability of the energy classification allows buyers and tenants to better understand the thermal quality of a home, a crucial asset for the value of the property.
…but biases that persist
However, inconsistencies remain. An essential concept to take into account is the primary energy conversion factor. This is used to convert final energy (that consumed directly by the home) into primary energy (that required for the production and transport of this energy). For electricity in France, this factor is set at 2.3, which means that 1 kWh of electricity consumed corresponds to 2.3 kWh of primary energy.
This factor is criticized because:
- It penalizes homes heated by electricity by overestimating their environmental impact, particularly compared to gas.
- It is based on an obsolete methodology, defined at a time when the French energy mix included more fossil fuels.
- It introduces a bias in the evaluation of thermal sieves, classifying certain electrical housing as F or G even though they benefit from low-carbon electricity.
Since 2021, this factor has been lowered from 2.58 to 2.3, but some argue for a value closer to 1.5 to better reflect the current reality of the energy mix.
Concerning small areas, the reform of July 2024 has already adapted the calculation method in order to correct the distortions observed. This revision provides a response to criticism concerning the penalization of housing of less than 40 m², which suffered from an overly severe assessment of their energy performance.
Another pitfall: the economic impact of this reform. The renovation requirements weigh heavily on owners, who must undertake sometimes costly work to keep their homes on the rental market. This financial pressure could result in a shortage of rental supply and an increase in rents, paradoxically contrary to the initial objectives.
What are the avenues for improvement?
If the DPE is an essential tool for guiding public policies, it must evolve to be fairer and better adapted to the realities on the ground. Three levers could be considered:
- Refine the calculation method to better take into account the specific features of old buildings and small surfaces.
- Provide further support to owners with increased financial assistance and easier access to expert advice to avoid errors in interpreting the diagnosis.
- Encourage innovative technological solutions, such as artificial intelligence, to refine renovation recommendations and optimize costs.
A criticized but essential tool
The DPE suffers from a lack of reliability due to insufficient or imprecise data. Diagnosticians, often deprived of complete information, find themselves forced to enter default values. This leads to inconsistent results, reinforcing citizens' mistrust. Standardized calculation methods ignore the specificities of buildings and the actual uses of occupants. These shortcomings compromise the effectiveness of this crucial tool.
The energy transition of the housing stock is a necessity, but it must be done in a fair and pragmatic manner. The DPE, if it wants to be a real driver of change, must continue to adapt to prevent it from becoming too heavy a constraint, to the detriment of owners and the real estate market as a whole.
Tribune by Eric Houdet, Founder of Homapi (LinkedIn).
