This article discusses two important tools used for energy analysis and thermal performance analysis of buildings - IES and BersPro. It explains their features, limitations, and applications in achieving energy efficiency and sustainability in construction. The article also highlights the importance of achieving CO2 emissions reductions and thermal comfortability in buildings. The IES tool is widely used by different professionals such as engineers, architects, planners, interior designers, and consultants in green energy and green building. The BersPro tool is used for simulation and analysis of the thermal performance of houses in Australia. It is an important tool for decision making on the key processes which must be utilized to improve the thermal production for the buildings.