An Energy Recovery Unit (ERU) is a type of HVAC system that is designed to help reduce energy consumption and improve indoor air quality. It works by recovering energy from the air that is being exhausted from the building and using it to pre-condition the incoming air. This helps to reduce the amount of energy needed to cool or heat the building, as well as reduce the amount of pollutants that are being released into the environment. ERUs are becoming increasingly popular as a way to reduce energy costs and improve air quality. They are also becoming more affordable and easier to install, making them a great option for businesses and homeowners alike.