BBC Housing, Saint-Brice-Courcelles

Project overview: 

At the client's request — keen to deliver energy-exemplary housing — COSTE Architectures designed an ensemble of 13 homes following bioclimatic principles.

The homes are split between 5 three-room (T3) and 8 four-room (T4) units, all built on the same volumetric and architectural principle. The houses face south and offer a generously lit living room opening onto a private garden. The living spaces are therefore all placed on the south façade and served by service spaces on the north side, which act as a buffer zone on the cold north façade.
Openings are mainly placed to the south to make the most of solar gains. The asymmetrical roofs feature a northern slope at 17% to optimise solar gains in winter, and a southern slope at 35% allowing solar panels to be installed for domestic hot-water production. The southern roof overhang, combined with adjustable and retractable brises-soleil on the large openings, effectively protects the homes from solar radiation, ensuring summer comfort.

The chosen construction system is timber framing with a load-bearing ladder system, allowing significant thickness and full air-tightness of the walls. The roof insulation, placed in a false ceiling, reduces the volume to be heated and offers the advantage of a cold-ventilated roof, limiting summer overheating.
The engineering firm AMOES, partner of COSTE Architectures, is in charge of thermodynamic simulations and has helped validate bold technical choices.
The ventilation is a simple dual-flow system with 90% efficiency. Backup heating is provided by a pellet stove placed in the living room. The placement of the main staircase at the rear of the living room contributes — through its brick walls — to the thermal inertia of the house. These walls act as a central radiator for both floors of the home.
Thanks to this design, these houses achieve a primary-energy consumption of 48 kWh-PE/sqm/year, while the reference value in the Reims region for BBC certification is 65 kWh-PE/sqm.