The invention relates to the construction industry. A solution is offered to increase the efficiency of heat storage by phase changing materials, as well as to direct the stored heat for heating buildings or hot water preparation. The proposed accumulation panel consists of phase change material, steel containers and a piping system. The melting point of the phase change material is between 20 and 23 °C. Thermally activated heat storage panel allows to control the change of the physical state of the phase change material and adapt it to the specifics of use.