With related greenhouse effect environmental issues linked to the constant problems of the fluctuations in oil prices, the use of solar energy is an important renewable energy source. Brazil is a country which is privileged considering the high rates of solar irradiation present throughout almost the entire national territory. Nevertheless, during certain times of the year, there is a solar energy deficit, which leads solar systems to require electrical resistance support at these times. The use of electrical resistance represents 23.5% of electric energy consumption and it presents a low residential energy efficiency. The purpose of this work is an alternative technical design for reduction of electric energy consumption through the use of a solar energy system together with a generating heat pump for water heaters for households, as well as the financial feasibility study on the use of this system. One such heat pump has been designed, constructed and tested experimentally. The average performance coefficient is equal to 2.10, a low value due to the use of a hermetic reciprocating compressor. Despite this low moderate price coefficient of acquisition and installation of a heat pump, one can allow a return on investment in from 2.1 to 3.3 years, whereas the equipment has a useful life of about 20 years, this period of return on investment is interesting.