A vertical wall made of cellular clayey concrete, which has been fitted with water pipes, is the subject of the study carried out herein under a heating mode of operations. The monitoring of this prototype＇s behaviour has been performed over 24-h cycles which include an 8-h period of water circulation. With both the material and the geometry of the prototype being held constant, the influence of energy-related parameters affected by water circulation, flow and temperature upon the amount of stored energy can be evaluated. It has been shown that within the particular domain of investigation, a variation in the flow does not engender significant fluctuations in the prototype＇s thermal performances. As the temperature of the intake water increases, the amount of energy stored in the wall also increases. Moreover, for a water intake temperature of 42 degrees C, the surfacic heat flow remains less than the maximal threshold imposed for floor-heating installations. A model, which has already been validated for other types of materials, is applied herein in order to simulate the prototype＇s behaviour. The comparison with an experimental series, which includes both a storage and a depletion phase, has shown a good level of agreement. (C) 2000 Elsevier Science S.A. All rights reserved.