Air curtains serve as an element separating the internal and external environment. The principle of operation of these devices is based on creating an air stream of high intensity, usually directed vertically downwards or at an appropriate angle, creating an invisible barrier for two environments with different values of pressures, temperatures, humidity, etc. The air curtains can be used to create an invisible barrier for two environments. Air curtains are used to reduce energy losses used to heat or cool the room. When buying an air curtain, it is very important to choose the appropriate power of the device capable of resisting this air inflow. There are horizontal and vertical air curtains, warm, cold, double-flow, water or electric curtains.