A 1500 CFM make-up air unit is a type of ventilation system that is designed to bring in fresh air from outside and replace stale air that is inside. It is typically used in commercial and industrial buildings to maintain a comfortable and healthy indoor environment. The make-up air unit works by drawing in outside air, filtering it, and then distributing it throughout the building. This helps to keep the air quality inside the building fresh and clean, and it also helps to reduce the amount of pollutants that are present in the air. Additionally, it helps to reduce the amount of energy that is used to heat and cool the building, since the fresh air that is brought in is already at the desired temperature. Make-up air units are a great way to ensure that the air inside the building is healthy and comfortable, and they are an important part of any building’s ventilation system.