Solar thermal power is nowadays one of the trendiest topics in the construction industry, and it represents a valuable energy source of heating that reduces energy consumption. As solar panels produce heating during the day and consumers demand calefaction during the whole day, we use standby tanks (for domestic hot water) and buffer tanks (for heating) for storage. The latest developments improved the efficiency and useful life while reducing the volume of tanks. So, the presented research work deals with analyzing the solar thermal power in a family house. This work presents a method to create a decision support system to compare solar energy systems in houses from economical, technical, availability, and environmental concerns. The weights of the criteria selected considering the analytical hierarchy process are computed. Parameters required for energy production calculations (location, temperature, etc.) and energy consumption (inhabitants, outdoor temperature, etc.) are summarized. It can be stated that a universal best solar thermal scheme does not exist, as energy consumption depends on the other features and limits as well as energy production, geographical latitude of the location, and so forth. According to results, Case 3 (a gas boiler and a combination tank) is the best alternative for reducing the energy required, CO2 emitted, the best energy efficiency of the installation, and the lowest transmission losses. In other scenarios when the economic criteria are not so relevant, this should be the best case in the prioritization scheme.