Optimal cutting conditions, which lead to a high quality of the machined surface and low energy consumption, are crucial for wood processing. This paper describes the effect of feed speed, cutting speed and mean chip thickness on energy consumption and saw blade surface temperature during the spruce (Picea excelsa) cutting process. In the experiment, the energy consumption and the surface temperature of the saw blades were measured to find the optimal cutting conditions for the energy-efficient cutting process. The surface temperature of the circular saw blade was monitored online using a non-contact infrared sensor connected directly to a PC via a USB connector. The results show that the cutting power and the surface temperature of the circular saw blade increased with increasing feed speed. The lowest values of cutting power were shown by the saw blade CSB3. Compared to the classic CSB1 circular saw blade, the values were lower by 8%. The surface temperature of the circular saw blade is highest at the outer edge (area of the heel of the teeth), and decreases towards the center of the circular saw blade. For an identical mean chip thickness, energy-efficient cutting was achieved at a feed speed of 21 m/min. There must be a trade-off between machine productivity and energy consumption. Monitoring the cutting process of circular saws using intelligent sensors is the way to adaptive control systems that ensure higher quality of the machined surface and cost-effective machining.