All new buildings must be nearly zero-energy buildings (NZEB) by 2020, and all new buildings occupied and owned by public authorities must be NZEB after 2018. These targets are set in the European Member States according to the EU directive on the Energy Performance of Buildings [1]. It is a huge challenge is to achieve these goals in northern countries where traditional energy saving measures – insulation, window performance, heat recovery from ventilation systems - balance on the border of cost optimality. New solutions have to be implemented in the field of energy saving and storing. The biomimicry approach imitates processes found in nature to solve human problems that can provide conceptually new solutions. The example of northern mammals can serve as inspiration – fatty tissue functions as thermal insulator of the body, but phase change properties of the lipids are also used to store and release heat. Phase change materials (PCM) have received much attention as an alternative for energy saving and storing. The energy demand for heating the building and thus CO2 emissions can be reduced by the amount of latent heat stored in PCMs. Lately different concepts on PCM integration in the building envelope are emerging – built-in walls, ceilings, floors, as a thin layer or large storage tanks. In order to create new PCM integrated building components – a solar thermal façade system appropriate PCM has to be chosen. This paper reviews the selection of PCM in melting temperature range 21–22̊C.