Energy is an important development factor. It is consumed in different format from different sources in daily human activities. Solar energy, as the most fundamental renewable energy resource, serves in a clean, domestic
and environmentally friendly way with minimum impact on surroundings. Due to the ability of transferring heat from low temperature to high temperature, heat pump systems can make great use of natural resources and
waste heat resources for the purpose of space heating. Based upon this theoretical principle, this paper presents an investigation on the performance of air source heat pump (ASHP) system with new environment friendly refrigerants, such as R1233zd(E), R1234YF, R1234ze(Z) and R1234ze(E). At the same time, some conventional refrigerants (R134a, R245fa and R123) have been investigated as well for results comparison. A MATLAB program has been developed with the assistance of the database of CoolProp. The results show that the use of some selected environment friendly refrigerants in air source heat pump system for building application alongside other refrigeration applications in strongly recommended.