A methodology for the Energy Retrofit of 20th Century Architecture: the Modèle Innovation La Salamandre

Since the 1970s, in response to critiques of the Grands Ensembles, French housing policy shifted toward innovative, small-scale projects. The Plan Construction (1971) supported residential research through the Innovation Models (1973-75). Among them, the Salamandre residence in Villeneuve d’Ascq (1979), by André Wogenscky and Sud Atelier, applied Modernist principles, with 422 units and design features inspired by the Modulor. Later alterations (1994-96) in the rental section changed its appearance without improving energy performance. A first research phase showed that user behavior accounts for up to 40% of energy demand. Empirical occupancy-based scenarios indicated a 6–8% reduction in heating needs compared to regulatory models. Based on this, a minimally invasive retrofit strategy – 'Réhabilitation 2.0’ – was proposed, involving residents and real-use data. Recent developments include tools for managing energy data to guide low-impact, heritage-respecting interventions.