Air curtains are devices installed over doorways or openings to create a barrier of air, effectively separating indoor and outdoor environments. They work by emitting a controlled stream of air across the entrance, forming an invisible curtain. The primary purpose of air curtains is to prevent the exchange of air, dust, pollutants, and insects between the two spaces while allowing easy passage for people and objects. Widely used in commercial and industrial settings, air curtains contribute to energy efficiency by minimizing temperature loss and reducing the workload on heating, ventilation, and air conditioning (HVAC) systems. They enhance indoor comfort, maintain cleanliness, and are commonly employed in retail, hospitality, manufacturing, and healthcare environments.