This paper shows the investigation of the features of facade greening, concerning the reduction of heat demand in the winter. Supporters of facade greening claim that their systems can reduce the heat demand in the winter. But so far, there is no proof for that and each greening system is different. Two greened facades have been researched and measured for one heating season. The measurements were compared with parts of the same buildings which are not greened. So far there does not exist a general method, how to calculate the U-value at greened facades. The method which is developed in this paper makes the comparison between the greened part of the facade and the not greened part possible. It turned out that there is a difference of the thermal resistance between greened and not greened parts of the facades in winter. It is between 0,31 m(2)K/W and 0,68 m(2)K/W depending on the greening system and its location. (C) 2016 Elsevier B.V. All rights reserved.