Prescribing and modeling renovation works using Energy Efficiency Rating Scales - Socio-technical and economic analysis of a public policy instrument – PREMOCLASSE

The expected and observed effects of the EPC-based retrofit policy in France were studied by means of several empirical sociological surveys based on interviews and analysis of press clippings (surveys of actors involved in the regulatory and legislative reform of the EPC, survey of the multi-family renovation sector, survey of private landlords, survey of real estate agents). They have enabled us to develop our knowledge of the design of the EPC as a public policy instrument, the dynamics of the renovation sector and the actual functioning of real estate markets.

The likely impacts were investigated through technical-economic studies that simulated retrofit work packages and their costs to achieve all EPC labels and for different types of housing. Prospective modelling work was also carried out using an enhanced version of the Res-IRF model developed at CIRED since 2008. The model now takes into account the technical characteristics of the modeled houses (envelope insulation, system performance). The new model now makes it possible to anticipate the technical consequences of public policy choices in terms of renovation (energy mix, GHG emissions, need for grid reinforcement, etc.).

The project has developed socio-economic knowledge and foresight on the dynamics, costs and technical options of housing renovation in relation to the EPC in France. These are illustrated in several publications resulting from the project, such as the "notes de synthèse" published on the premoclasse.fr website, in particular the one dedicated to landlords. This was the topic of presentations to the ANAH and to France Rénov consultants. Some of the results of the project were used in a note written by L-G. Giraudet and L. Vivier, CIRED researchers and members of the project, for the Conseil d'Analyse Économique, entitled "Analyse socio-économique de la rénovation énergétique des logements", published in June 2002. French public authorities rely on the enhanced version of the Res-IRF model, notably in the context of the National Low Carbon Strategy (SNBC).

The project has resulted in several international scientific publications in peer-reviewed journals, including Environmental Research Letters, as well as numerous presentations at international and national conferences. Some of the socioeconomic part of the project were the subject of an invitation to a seminar at the Collège de France.

Two days of conference organized in Paris in March 2024 also brought together a research community in sociology, economics and architecture.

This work was carried out at an opportune time, at the same time that renovation policy was gaining in importance among public transition policies, and when the EPC had become a central instrument. It has produced knowledge that is directly useful for public decision-making (use of Res-IRF for the SNBC). There is no doubt that the project's researchers will continue to promote and develop their work in the years to come.

In progress

In the building sector, the organisation of retrofit markets heavily draws on information and standard-setting devices developed by the public authorities to shape the action of companies and customers. The PREMOCLASSE project questions the role of one of them: the Energy Performance Certificate (EPC).

While EPC is now mainly used, by legal obligation, on the real estate transaction market, its role is increasing in governmental efforts at steering energy renovation of buildings. The PREMOCLASSE project proposes an alliance between disciplines and approaches to analyse the different roles of EPC in the renovation sector. It particularly seeks to understand the relationship between two aspects that are only partially related in current practices: on the one hand, the measurement of energy performance by the EPC, and on the other hand, the implementation of specific retrofit works to improve it.

The projects intends to make three different contributions.
1. In the field of social sciences, the project will develop research on the role of EPC in shaping energy renovation policies and, more generally, on the mobilisation of valuation instruments and processes in socio-political and economic change. The contribution will be both conceptual (development of the links between the sociology of public action and markets and the sociology of energy and building) and empirical (the case study of the EPC will be fully documented from the socio-historical angle and from the angle of socio-professional practices in the fields concerned).
2. In the field of modelling, the project will contribute to enriching and improving an integrated energy-economy modelling tool for the housing stock: the “Res-IRF” model. The aim will be to improve the descriptive capabilities of the tool by including the types of renovation work that can be done. It will also seek to improve its robustness by integrating sociological data that can increase the realism of the modelling.
3. In the field of energy assessment; the project will build scenarios for the composition of the residential housing stock by 2050 based on close cooperation between sociological, technical and economic approaches. Interdisciplinarity will be exercised upstream in the definition of hypotheses and downstream in the analysis of results leading to original scenarios of building stock evolution.

By combining disciplines that are often specialised in analysing specific sub-segments of energy policy (engineering sciences, sociology, economics), the PREMOCLASSE project takes an original position in the still fragmented field of studies on buildings, energy systems and renovation. However, it goes beyond what these approaches usually propose. First, it includes both fundamental dimensions (modelling, social sciences) and application dimensions (prospective scenarios). Second, it makes both a positive (optimisation of modelling, knowledge of the practices of professionals in the field, development of scenarios) and reflexive (feedback between measurement and what is measured) contribution to addressing the challenges of energy renovation in housing. Finally, and this is one of the distinctive characteristics of the project, it brings knowledge specific to EDF R&D (technical-economic approach to buildings, knowledge of the types of works and prices for energy renovation) toward more open academic research.

The fact that EDF R&D, Armines and CIRED are combining their expertise on the subject of the economic efficiency of energy renovation has a scope that goes far beyond these organizations. Indeed, Premoclasse results will form a knowledge base and proposals that can be mobilized for future developments of EPCs (enforceability, environmental performance, etc.). Also an appropriation of the Premoclasse results by public and private actors in the energy renovation sector could allow an optimization of the economic instruments to encourage and make the renovation more reliable.