The submitted thesis is based on the analysis of reducing the energetical difficulty of circular saw, what is considered important today with every company building around it. Huge capacity (efficiency) is needed from the circular saw based on the volume of timber and the amount of crafted pieces of precise size for the lowest energy consumption possible. Consumption of electricity is dependent on different energy types, such as thermal energy and the sonic energy, created while sawing the wood. We will be able to rate and choose with the analysis of these energies and modifications of circular saws, which circular saw is the most efficient with the least energy consumption.The thesis is divided into multiple parts. Characteristics of kinematic calculations of circular saw, different types of measuring and efficiency influence are in the intro. There is also shown the example and description of different types of circular saws for cutting along the lines from the worldwide brand Leitz. In theoretical part are written the methods and tools used for contactless thermal measuring.The next chapter is experimental, it is written the description of samples‘ preparing and the description of tool on which the experiments were done. It also shows us the example of used circular saws and differences between them, such as efficiency and temperature between the individual circular saws. The next chapter is the processing and reviewing the measured values. Their analysis has helped us with comparing circular saws and choosing of the most energy efficient.