This paper classifies green envelopes as green roofs and green walls according to effective factors, which were derived from literature to compare the green envelopes’ thermal and energy performance in a more effective way. For this purpose, an extensive literature review was carried out by searching keywords in databases and studying related journal papers and articles. The research method for this study was bibliographic and logical reasoning. The paper proposes five classification factors: contextual factors, greenery factors, scale factors and surface and integration factors. It also demonstrates the influence of physical and geometrical properties of plants and their supporting structures on the thermal performance of green envelopes. The paper argues that climatic conditions also have an important role on the thermal behavior of green envelopes and it determines the types of greenery integration into building envelopes.