PVsyst is a PC software package for the study, sizing and data analysis of complete PV systems. It deals with grid-connected, stand-alone, pumping and DC-grid (public transportation) PV systems, and includes extensive meteo and PV systems components databases, as well as general solar energy tools. PVsyst is designed to be used by architects, engineers, and researchers, as it is able to import meteo data, as well as personal data from many different sources. It includes a detailed contextual Help menu that explains the procedures and models that are used, and offers a user-friendly approach with a guide to develop a project. It has to be installed on the workstation where it will be used, and only runs for Windows.