Habitat Social Positif (HSP) grew out of an initial discussion between the Mayor of Castelnaudary and Terreal Group CEO Hervé Gastinel, who shared the ambition of using locally available skills to build a positive-energy home as a prototype for the homes of 2020. HSP is a collaborative project for building positive energy houses that are cheap, robust and comfortable all year round from locally made construction products.

What will the homes of 2020 look like?

The home of 2020 will be a positive energy building (a bâtiment à énergie positive or "BEPos" in French). This means it will consume less energy than it produces. The definition of a "BEPos" was introduced by the Grenelle I Law of 3 August 2009 and similar provisions can be found in the European Directive on Energy Performance in Buildings (Directive 2012/27/EU, adopted on 25 October 2012). The home of 2020 will produce enough energy to offset:

  • the energy consumed by the building for heating, lighting, domestic hot water, ventilation and auxiliary services
  • the energy consumed by the occupants (for domestic appliances, computer equipment etc.)

The home of tomorrow must be the fruit of collaboration between everyone involved in the building process, and It should consider sustainable development in its overall context. In other words, it is not only a question of the energy performance of the building, but also of its being economically viable, easy to run, robust and reliable over time, comfortable all year round (especially in the hottest months), accessible to the disabled and respectful of its surroundings.

 Bepos Effinergie certification

The future exists now

HSP is made up of two houses, one two-bedroom and one three-bedroom, which consume less energy than they produce. They have been built in the Les Vallons du Griffoul eco-district in Castelnaudary, using sustainable, locally made construction materials. Their performance has been certified under the "Effinergie +" and "Bepos Effinergie 2013" standards, meaning they exceed the minimum requirements of RT2012.

The houses belong to the social housing provider Habitat Audois.

Their real-life energy consumption and comfort levels will be measured and studied over a three-year period with tenants in place, so that we can learn more about what the positive energy home of tomorrow needs in order to succeed.

Simple and robust in everyday use, without relying on overly sophisticated technology, they will demonstrate that low energy use is compatible with construction solutions that are available today and meet the budgetary requirements for social housing.

Results and findings from Project HSP will thus provide the template for other projects both locally and further afield.

Building the future in Castelnaudary

Project HSP (short for Habitat Social Positif) was conceived in order to:

  • take an exemplary holistic approach to the process of construction, and
  • learn and understand how to be ready for the transformations that the construction industry is set to undergo.

Project HSP is a model local project conceived by the key stakeholders in the Languedoc Roussillon Region

The Languedoc Roussillon Region has identified a number of key issues for the future: a need for high-performance homes to address demographic growth (30,000 new residents per year) and the risk of climate change (the Climate 2030 Plan), the need for a construction industry that promotes occupational training and cross-skilling, and a desire for concerted action among all the parties involved in design and construction. The Regional Council, in full cooperation with the regional agency of ADEME, has therefore decided to give technical and financial support to model projects and apply the innovative experiences gained in amenity provision, town planning and environmental matters on a region-wide basis.

The Municipality of Castelnaudary's infrastructure plan for phase 1 of the Vallons du Griffoul development zone is an ideal fit with the plans laid down by the Region.

Castelnaudary's eco-district: Les Vallons du Griffoul

In 2010, the Vallons du Griffoul development zone won the "New Sustainable Urban Forms" prize awarded by the Languedoc Roussillon Region.

Designed on the lines of an eco-district, it offers homes of various types in an innovative, sustainable neighbourhood. It reflects the needs of the population while respecting both environmental requirements and the town's identity.

As part of its sustainable development policy, the Municipality of Castelnaudary has drawn up a plan to limit environmental impacts, keep energy use down and pay special attention to environmental quality in the new zone, which is designed to be an eco-district that combines low resource use, densification and a mixed housing stock while creating close links to nature, farmland and water.

The eco-district will complement the existing town plan, in accordance with the municipality's sustainable development objectives:

  • Urban form and integration: height restrictions, reduced car use, provision of cycleways and pedestrian routes, easy access to public transport.
  • Mixed housing: housing will be a mixture of individual houses, small developments and apartment blocks; one quarter will be social housing.
  • Water: rainwater collection, low-consumption equipment, welcome leaflets for new occupants.
  • Biodiversity: conservation of wooded areas.
  • Bioclimatic orientation: south-facing living areas.
  • Energy: low-energy buildings with solar hot water.
  • Waste: waste-sorting areas and composters.
  • Materials: local, natural, certified.
  • No excessive costs.
  • Collective action.


TERREAL makes terracotta construction solutions for building envelopes. Operating in the Aude since 1855, the company is an important and long-standing contributor to the local economy. It employs over 350 staff in the Castelnaudary area, which is also home to its Research & Development Centre. Both modern and firmly rooted in the region, the company has a genuine commitment to training, innovation and sustainable development.

Studying the issues surrounding the building of 2020 enables TERREAL to find the solutions of the future, sustain its business and maintain employment, in line with its corporate social responsibility goals of:

  • Protecting the environment by controlling environmental impacts
  • Providing a social housing project with access for the disabled
  • Keeping construction and usage costs down
  • Training young people and others in the industry

Locally made construction materials

The materials used in the building of these houses are made at TERREAL's plants in the Languedoc-Roussillon and Midi-Pyrénées regions. Over 630 people are employed at the various production sites.

The clay and sand used to make the bricks, roof tiles and other exterior decorative and structural products chosen for the HSP houses are sourced from quarries sited within a limited radius.

Production of these items cannot be transferred outside the region, and the intrinsic quality of the finished products sold by the TERREAL Group is dependent on the quality of the raw materials.

Product life cycles have been analysed. FDES sheets (environmental and health declaration sheet) are available for several of them free of charge on the database at www.inies.fr, or alternatively on request from TERREAL.

  • Colomiers: TERREAL Calibric TH Evolution and TERREAL terracotta partitions
  • Lasbordes: TERREAL monolith fittings and TERREAL BMI 30 insulated monolith bricks
  • Ségala: TERRAL DCL terracotta roof tiles

Lahera: TERREAL LaheSafe airtight insulating shell; TERREAL Solterre TH2 solar heating system; TERREAL Solterre PV solar electricity system and TERREAL LaheRoof heat recovery system

Our commitment to a presence in the region contributes to the development of local life.