"The paper proposes a method of use of the accumulated surplus of solar water heating installation, the major element of which is the solar collector for heating of greenhouses. The heat energy, which was preserved in the battery for the summer months, can be used for heating of greenhouses in the autumn and winter months. The proposed method will significantly increase the efficiency of the solar collector and reduce the term of recoupment. This development will be relevant for the individual dwelling houses, with garden plots sufficient to build greenhouses there. The use of ""Energy - Effective"" greenhouses combined with solar water heating unit, significantly reduces the cost of electricity and heating. The use of low-grade thermal energy from the sun and soil is the main direction of development of energy-saving technology of housing and communal services. "

Keywords: solar collector, energy efficiency, energy-saving, low-potential energy, alternative heat source.