Energy renovation of housing: Cerema deciphers the decision-making support systems for the work to be carried out

Climate and Resilience Law

To sell or rent a home, owners have the obligation to carry out a DPE in order to identify the classification of their property.

If this housing is classified E, F or G, it is considered an "energy sieve" and is a priority target of public policies for the energy renovation of the housing stock contained in the Climate and Resilience law.

Additional investigations are therefore obligatorily carried out within the framework of an Audit or a Multiannual Plan of Works in co-ownership to define the necessary energy renovation works.

In the absence of this work, the owners would be forced with regard to a proposed schedule:

• freezing of rents on 1 January 2023 for housing G and F;
• to the rental ban at:
  • January 1, 2025 for housing G;
  • January 1, 2028 for Class F accommodation;
  • January 1, 2034 for Class E accommodation.

The Energy Performance Diagnosis

Since 2021, the DPE concerns all housing offered for sale and rental as well as new constructions. It is carried out by diagnosticians with or without mention depending on the type of ECD to be carried out. The 3CL 2021 calculation model is the one imposed by the regulations.

5 consumption items are taken into account in the calculation. Consumption of heating, domestic hot water, cooling, consumption of lighting and auxiliaries for ventilation, generation, distribution, heating, cooling and domestic hot water are included in the calculation.

The DPE integrates indicators such as summer comfort, or the overall performance of the envelope. It displays a dual Energy/Carbon threshold. In addition to the level of performance for energy, which gives visibility on the consumption of housing, it informs about its emissions of greenhouse gases (CO2) into the atmosphere.

The DPE brings new legal guarantees to the consumer. All data entered in it must be justified.

There are different types of DPE input data:

• estimated data: the age of the building is the only data which remains subject to interpretation, and which can be estimated;
• observed or measured data: living area, measurements of heat loss surfaces, thickness of glazing, equipment installed, presence and thickness of insulation if it is accessible (in the attic for example);
• data obtained from a supporting document: all other input data entered must be justified, using a supporting document from among those listed in the regulatory texts. Evidence is used only if the item is neither measurable nor observable.

For all unjustified data, the default value should be entered. This default value is penalizing and can degrade the housing rating.

Realization of a DPE in a collective residential building

There are two methods for carrying out an ECD for an apartment in an apartment building. The first is to carry out the ECD in the apartment, by applying specific rules. This solution will be more economical in the case of a small condominium, where each unit can be rented or sold independently of each other. It makes it possible to have DPEs representative of the property, whatever the scenario encountered.

The second method consists in carrying out the DPE in the apartment by adapting the data of the building according to the methodology developed in the appendix of the guide for the attention of diagnosticians. This solution will be more economical within the framework of a homogeneous management of the apartments, or within the framework of a large joint ownership with frequent sales or rentals of apartments. (Article R. 134-4-3 of the Construction and Housing Code).

In any case, the diagnostician may need data held by the co-ownership for all common installations. The owner of the building or the syndic of co-ownership are obliged by the regulations to provide them to the person requesting the DPE (Article R. 134-3 of the Construction and Housing Code).

The DPE therefore contains the classification before and after the works, the estimate of the energy loads, educational indicators (thermal balance, summer comfort, performance of each element), etc...

The recommendations are presented in 2 packages of work:

• a package to get out of the energy sieve state for F or G classified housing, or to improve energy performance for buildings already classified E or better,
• a bouquet enabling energy class A or B to be achieved.

This work must obviously not increase the quantity of greenhouse gases emitted. No recommendation is made for new construction.

Its validity period is 10 years.

The energy audit

The "Climate and Resilience" law has added to the DPE an obligation to carry out an energy audit for all energy-intensive single-ownership residential buildings offered for sale. This obligation applies on April 1, 2023 for F and G housing, on January 1, 2025 for class E housing and on January 1, 2034 for class D housing.

The energy audit is a complementary document to the DPE which comes after it has been carried out. The DPE presents recommendations for improvement for information purposes, while the audit includes more specific work scenarios.

The energy audit is also established by diagnosticians, by architects, design offices and companies. The calculation model is the same as for the DPE.

The audit contains a general inventory of the property, an estimate of the performance of the building, proposals for work allowing the achievement of an efficient renovation, etc...

Two proposals for work paths are present in the energy audit: a first proposal provides for a work path in stages to constitute an efficient renovation and a second proposal provides for a work path in a single step to constitute an efficient renovation.

The work path integrates the processing of 6 work stations:

• wall insulation
• low floor insulation
• roof insulation
• replacement of existing joinery
• ventilation
• the production of heating and domestic hot water as well as the interfaces.

In addition, for each type of work, the energy audit describes the minimum performance criteria to be met with regard to regulatory provisions or to benefit from financial aid. It also incorporates additional work to guarantee sufficient air renewal when necessary.

Its validity period is 5 years.

The course of work provides for the processing of six work stations and makes it possible to achieve at least:

• performance class C for class E buildings before works;
• performance class D for class F buildings before works;
• performance class E for class G buildings before works.

Global Technical Diagnosis

The DTG is used to inform the co-owners of the overall technical condition of the building and lists the work to be carried out.

It is mandatory for certain condominiums. If it is demonstrated by the DTG that work is necessary, the syndic has the obligation to include on the agenda of the general meeting the question of drawing up a multi-year work plan.

The DTG is carried out by a professional such as a design office, a thermal engineer or a real estate diagnostician. This professional must attest on his honor to his impartiality and his independence with regard to the syndic and with regard to the energy suppliers and the companies intervening on the building and justify having taken out civil liability insurance. professional.

This diagnosis includes:

• An analysis of the apparent condition of the common areas and common equipment of the building.
• A statement of the situation of the syndicate of co-owners with regard to legal and regulatory obligations in respect of construction and housing.
• An analysis of possible improvements in the technical and asset management of the building.
• A diagnosis of the energy performance of the building.
• A summary evaluation of the cost and a list of the work necessary for the conservation of the building, the preservation of the health and safety of the occupants and the achievement of energy savings. This assessment must in particular specify the work that must be carried out in the next 10 years.

The conclusions of the DTG must be provided to the future buyer of a co-ownership lot.

Multi-Year Work Plan

The energy audit obligation in co-ownership of more than 50 lots has been replaced by a multi-year work plan (PPT) since January 2020. This is a document made by the co-ownership to set up a work schedule over a period of 10 years. It concerns condominiums over 15 years old. It must be updated every 10 years to supplement the work fund which must be validated at the general meeting of co-ownership. The building must be intended for total or partial habitation.

The syndicate of co-owners must put in place a draft multi-year work plan (PPT) at the end of a period of 15 years from the date of acceptance of the building.

The new rules of the PPT and the works fund come into force gradually on January 1, 2023 for co-ownerships with more than 200 lots, on January 1, 2024 for those with between 51 and 200 lots and on January 1, 2025 for co-ownerships comprising at most fifty lots.

This plan should be written by the same professionals as those for a DTG.

The syndicate of co-owners may be exempted from this implementation if the DTG shows no need for work during the 10 years following its development.

The PPT must necessarily be based on the DPE for the initial state and must display the DPE projected at the end of the work of the plan.

The work prescribed in the PPT and its schedule must be included in the building's maintenance log. As with the DTG, once the PPT project is completed, the syndicate must present it to the 1st general meeting of co-owners following its development.

Thermal Regulation of Existing Housing

The renovation work program must also take into consideration compliance with thermal regulations. For housing renovation work, the thermal regulations for existing buildings (Existing RT) apply in 3 ways: overall RT, RT element by element and "on-board works decree".

The "global RT" does not apply to buildings built before 1948 and concerns global renovation works with thermal calculation using the regulatory calculation engine.

The "RT element by element" is defined by the Order of May 3, 2007 relating to the thermal characteristics and energy performance of existing buildings.

The "Decree on-board works" concerns the replacement of the roof or the renovation of the facade, it is necessary to ship insulation except to justify why it is not done for heritage, technical, economic or structural reasons.

For more information, see the Cerema website.