Abstract: Covering material for walls, facades, roofs or the like, which is flown through by a heat transfer medium for the assimilation or absorption of radiant heat and/or heat from the environment and by which the shape and/or size of the cross-section of the flow channels for the heat transfer medium is variable by change of the pressure in the flow channels, for example, by change of the pressure in the heat transfer medium for knocking off the ice and/or snow edges as well as for the change of the free cross-section for the heat transfer medium. Further, a distributor or collector channel molding is provided with which the covering material can be connected into the circuit for the heat transfer medium.