An endothermic system works by circulating heat transfer fluid, using a circulation pump through the energy collectors intergrated into the building. The collected energy is transferred to energy stores from where the thermal energy is  upgraded by a heat pump as it is needed. Therefor the heatpump is the central and most vital element  in the overall system. Its efficiency governs the effectivness of the system and therefore it is vital to have a hight coefficients of performances (COP). a viarity of energy collectors can be used to provide the freely available thermal energy to drive the system so that effective space heating and hot water can be provided to the building. The technology can also be used for space cooling.