In the last decade the interest for electric production using PhotoVoltaic System (PVS) has strongly increased; namely for the citizen who is able to use roofs or personal surfaces to put in place such systems. For instance, the installed residential PVS capacity has grown to 550 MW (Megawatt) in metropolitan France during the last years. The same trend can be noticed in many developed countries at the same time. However, in light of this investment, people would like to be informed of the different aspects, especially the economic and environmental ones, in order to make their choice. In this sense, this paper deals with the decision-making problem for the residential PVS investment. Different alternatives of module surfaces and PV technology installation are considered and a procedure founded on the ELECTRE approach to aid the citizen in his choice is proposed.