Energy evaluation of rammed earth walls using long term in-situ measurements

Available throughout the world and used in construction for thousand years, earthen materials are known to improve indoor air quality while keeping the internal temperature relatively stable. In Rhône-Alpes, France, the rammed earth technic is the most spread and consists in compacting layers of earth, one by one, within a framework. Current thermal standards, which are mainly based on thermal resistance of the material, urge to insulate walls. However, due to its interaction with its environment, and its couplings between heat and moisture transfers, the observed thermal behaviour of uninsulated rammed earth can be above the expectations. The objective of the paper is to highlight the living comfort provided by non-insulated rammed earth walls, for different orientations, from in-situ measurements performed over more than two years. Winter, with low energy use for heating, and summer, with no cooling device, are studied. The study points out the important role of solar irradiance on the thermal balance of the house, and thus the importance of a good architecture.