This paper presents a hardware-software application for the study of built hybrid hot water supply systems functioning year-round and using solar energy and additional heating sources. It compares the achievable efficiency of the constructed systems with design calculations. The application uses a new computer-aided application that allows controlling the operation modes of systems, accumulation and transmission of the obtained data over long distances, its processing and presentation in the required table or graphical format. This application is used to analyze the effectiveness of a solar hybrid hot water system located in the city of Yakutsk. The system includes three groups of evacuated collectors, three header tanks and a gas boiler. For this system, experimental data are given on hourly, daily (on working days, weekends and holidays), monthly and annual operation modes. It was established that the annual solar fraction is 0.29 and it does not correspond to the design estimate of 0.51. The temperature of the water supplied to the consumer in the cold six months at a daily flow rate of 4 m3/d is 47 ± 3.1 °C, which lower than the design calculation of 57 ± 2.5 °C. Based on the analysis of the obtained experimental data recommendations are proposed to improve the efficiency of the system to the design level while reducing the consumption of natural gas. The paper also outlines the ways of improving the hardware-software application.