Case study 03 – Energy performance of a ‘Passive House’

The house was designed and built by Daniel Bayol of DB Chanvre, who specialises in this type of building.

Located in Vidauban (in the Var department), this modern house is positioned so as to make the most of the sun throughout the day, with very large south-facing windows.

  • Natural light floods in.
  • The sunshine is ideal for exploiting the heat storage capacity of the mud brick wall, which also serves to structure the indoor space.
  • The wide overhanging eaves that run right round the building serve to protect windows and the mud brick wall from over-exposure to the sun during the hottest period (from May to September). This means that the house does not get too hot when the sun really starts to blaze, as it can do in this region.

This is truly a bioclimatic house, where everything has been designed to get the best out of the positioning of the house and the materials used to ultimately reduce energy consumption and environmental impacts as much as possible.

Ossature bois porteuse poue cette maion passive

The timber load-bearing frame used in this passive house

Temperatures are dynamically regulated by the hempcrete

For example, when we visited the house at the end of January:

  • Outdoors it was 8°C
  • Indoors it was 19°C
  • Indoor relative humidity was 50%

With a very high level of thermal comfort and well-being

Eclairage naturel et grand espace intérieur pour définir cette architecture contemporaine

The interior where natural light has pride of place

Heating energy consumption

The heating bill for 2015 was €133 incl. VAT for the winter season running from November to end of March.


Passive House certification

  • The primary energy consumption (CEP) threshold for this certification stands at 120 kW/m²/year
  • The CEP for this 122 m² house is 113 kW/m²/year, or 6% less than the reference figure.


Construction system

  • Timber framing
  • Tradical® Hempcrete: thickness of 30 cm
    applied to walls via mechanical projection over three days. R=3.5 m²K/W
  • Double-flow CMV
  • Internal wall made of mud bricks to store the heat from the sun
  • Cellulose wadding
  • Solar thermal panels

Environmental Impact

43 m3 of Tradical® Hempcrete stores 3.6 t of CO2
Eligible for Level 3 Bâtiment Biosourcé (bio-based building) certification

Performance ratings

Maison passive en béton de chanvre

Six qualities that define this passive house

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