Across the entire Greek territory one may encounter several remote consumers that could cover their needs on the basis of PV-based stand-alone applications exploiting the high quality local solar potential. In this context, optimum sizing of such installations also involves investigation of the optimum panels' tilt angle, which opposite to grid-connected applications is required to provide year-round energy autonomy rather than maximization of the annual energy yield. Considering the above, investigation of the optimum panels' tilt angle for stand-alone applications is the aim of the specific study, in both theoretical and experimental terms. Theoretical investigation is based on the validation of the assumption that the optimum angle for such applications coincides with the angle that provides maximum exploitation of solar potential during winter months, while following, the optimum angle determined in the area of 60° is also experimentally validated with the conduction of long-term winter measurements for the area of Athens.