Resumen
The increasing consumption of electric energy used for heating water especially in peak periods, requires the use of alternative energy sources that meet the same needs being less costly. The use of solar energy for heating water allows reducing the demand and consumption of electric energy by a conventional electric shower. This study aimed at developing a software to simulate, design, and optimize a mixed water heating system (solar and electric), by using the software MATLAB. This software designed independently the area of a solar collector, the volume of the boiler, and the power of the auxiliary electrical resistance, in order to meet the needs of hot water and ensure the least annual cost. The optimized system when compared with the use of a conventional electric shower presented a time for return of the invested capital of around seven months.