In this study, a solar powered water source heat pump system was modeled through the TRNSYS program to meet the heating needs of two different types of greenhouses with different set point temperatures in Van climate conditions. These greenhouses are named as cold and warm greenhouses according to set point temperatures, and the set point temperatures are 6 ° C and 17 ° C respectively for cold and warm greenhouses. In two greenhouse systems, single layer glass and double layer polyethylene (ÇPE) greenhouse cover materials were used and annual heating energy requirements were compared. The heat loads of both greenhouses were calculated with the help of TRNSYS program and a sufficient capacity heat pump was selected accordingly. The nominal heating capacity and heat pump power consumption values of the heat pump used in the cold greenhouse system are 30000 kJ / h and 6000 kJ / h respectively, while the nominal heating capacity and heat pump power consumption of the warm greenhouse system is 64252 kJ / h and 17848 kJ / h, respectively. According to the results obtained in this study, as a result of the use of doublelayer polyethylene greenhouse cover instead of glass greenhouse cover in cold and warm greenhouse, saves 55% and 44% heating energy for cold and warm greenhouse, respectively.