There is scarce research in the domain of sustainable marketing and renewable energy (RE), despite the importance of this area. In this study, considering the theory of reasoned action (TRA), knowledge about RE (RE_KNOW), attitude toward RE (RE_ATT), willingness to pay more for RE (RE_WPM) and predisposition to ecological consumption behavior (ECCB) were analysed as determinants of the intention to use RE (RE_INT). The results of an online survey confirm all the determinants except RE_WPM. ECCB is the stronger determinant of RE_INT, followed by RE_ATT. A beliefs -attitude -intention link was established which supports the TRA. Furthermore, the moderator effects of sex and age were evaluated. For women and men, the proposed relations do not have significant differences. However, for the younger group, RE_ATT is the only significant determinant of RE_INT, whereas for the older, ECCB and RE_WPM are the significant ones.