Description

Residential buildings represent a major share of energy consumption and carbon emissions in France, particularly due to the use of heating systems in collective housing. Current estimates indicate that nearly two-thirds of building emissions originate from residential dwellings (Service de la Donn´ee et des ´Etudes Statistiques (SDES) 2024). Despite strong national ambitions in favour of energy transition, only a limited proportion of condomini-ums undertake energy renovation works. Recent evaluations suggest that approximately ten percent of condominiums engage in such works, which highlights the gap between policy expectations and actual outcomes (Agence nationale de l’habitat (Anah) 2024).
Energy renovation therefore constitutes two strategic challenges. It plays a central role in diminishing energy poverty, especially for vulnerable households living in poorly insulated buildings. It also represents a necessary condition for reaching the objective of carbon neutrality by 2050. Existing policies that focus mainly on individual houses tend to neglect condominiums, although collective housing is extremely prevalent in urban areas and exhibits substantial renovation potential. The collective nature of decision-making in condominiums creates additional constraints that are absent in the context of individual property ownership. Each renovation decision depends not only on the perceived benefits of a single owner but also on the willingness and capacity of all other owners to approve, finance and coordinate renovation works.
The coexistence of owner-occupiers and landlords, together with heterogeneous levels of income, time horizons and perceived benefits, generates coordination failures and may lead to systematic blocks in energy renovation (Brisepierre 2012). These specific features raise the central research question of this project: how can public or private actors effec-tively incentivize condominium stakeholders to engage inenergy renovation works despite heterogeneous preferences, asymmetric information and collective decision-making con-straints? This question motivates the present PhD proposal. The objective of the thesis is to create academic knowledge while producing operational tools for the evaluation and design of renovation incentives adapted to the collective context of condominiums.

Research Objectives
The thesis has three interconnected objectives. The first objective is to develop a theo-retical model of the renovation decision made by landlords. The model will incorporate uncertainty regarding rental income, resale value, and future regulatory conditions associ-ated with the energy performance of buildings. The model will use a real option approach to characterise renovation as an irreversible investment made under uncertainty.
The second objective is to integrate the individual model within the collective con-text of condominium governance. The decision to renovate a building depends on the aggregated choices of all owners and on the coordination mechanisms established by the condominium management structure. The project will therefore mobilise the Mean Field Games (MFG) framework to represent the strategic interdependence of many heteroge-neous agents. The MFG approach will be combined with principal-agent theory in order to model incentives designed by public authorities or condominium managers under con-ditions of asymmetric information. The third objective is to validate the theoretical model empirically and to use the results to evaluate different public policy instruments. The research will rely on econo-metric analysis, simulation methods and experimental economics. The goal is to estimate real-world decision thresholds, identify behavioural barriers to cooperation, and compare the effectiveness of alternative policy tools such as direct subsidies, subsidised loans and tax incentives.

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