- Contrat de Performance Energétique
Foncia | Neptune Residence
A major global renovation project for Foncia Boucles de Seine
Foncia Boucles de Seine undertook a project for the complete renovation of the Neptune Residence in the main square of Val Fourré in Mantes-la-Jolie outside Paris. Built in 1971, this complex of 72 homes was in a state of general disrepair, resulting in a poor image, high heating costs and a situation of thermal discomfort for the residents.
Work began in May 2021 and finished nine months later in early 2022. The project sought to respond to a growing demand for energy efficiency and thermal comfort for residents. The work was carried out by a consortium led by Bouygues Bâtiment IDF in collaboration with the Idex Group, which won the special jury prize in the local Trophées des Copros energy renovation awards.
Architectural strategy and energy performance
To meet these objectives, considerable thought went into the architectural approach. The idea was to enhance the building's strong points while simplifying the architecture, for a modern, residential look.
The complete renovation of the building envelope included repairing the insulation and waterproofing the roof terrace, applying thin render over the insulation on the facade, replacing the external joinery and insulating the upper basement floor.
Significant improvements were made to the ventilation system, which was converted to mixed mode, while the radiators were fitted with thermostatic valves. At the same time, the heating and domestic hot water systems were replaced, as was the substation for connection to the district heating network.
In the longer term, these comprehensive renovation efforts will cut energy consumption by 43%. This performance gives the residence an energy performance rating of B, with primary energy consumption of just 80.60 kWhpe/m2.year.
Prior to the works, greenhouse gas emissions totalled 15.97 kgCO2e/m²/year (C rating). Since the commissioning of the new facilities, this has now fallen to 8.00 kgCO2e/m2/year.
Broad support for the energy transition
Regular coffee events were held during the works, bringing together all the stakeholders, in particular the project management team, the contractors, the co-owners and the property managers. These events paved the way for improved communication, while raising awareness among co-owners of the challenges raised by the project, and encouraging their active involvement. Residents were able to express their preferences and described the experience as both satisfying and enriching from a social and human standpoint.
This project is part of the Orcodin national programme, the purpose of which is to turn residential buildings in a state of advanced disrepair into exemplary illustrations of the energy transition. The project is supported by the municipality along with the many institutional players involved in the energy transformation process: the project has received financial backing from the ANAH (61%), Habiter Mieux (4%), the Regional Council (28%), and GPSEO (Greater Paris Seine and Oise Urban Community) (5%).
The home owners have gained a sound, aesthetically pleasing and thermally comfortable building, with a guaranteed 43% reduction in actual heating consumption over a 15-year period.
15 years: contract duration
72 homes
43% reduction in energy consumption
104 kWh/m²/floor area: target thermal performance