In some building typologies with stable electricity consumption profiles in the middle hours of the day, solar photovoltaic technology has emerged as a source of energy that can replace a high percentage of the electrical supply from the conventional power grid. This paper analyzes the photovoltaic energy installations for self-consumption in public buildings of two types from the energy point of view, and reviews the financial aspects. To do this, a software tool which applies recognized models for the prediction of photovoltaic intraday productions has been applied. This tool compares the photovoltaic energy productions with the typical energy demand curves of thirty public buildings and makes the energy and economic balances. The analysis is used for the project decision making regarding the proper location for the installation of panels and the determination of the optimal design parameters of the self-consumption photovoltaic installations to be built in two of the buildings analyzed. In conclusion, for the typical profile of energy consumption of administrative and service buildings, such installations are of interest from the economic and energetic point of view discussed in the article.