Energy recovery ventilators (ERVs) are designed to improve HVAC system performance by taking the energy from exhausted building air and using it to precondition incoming outdoor ventilation air. This preconditioning reduces the load demand on the HVAC unit while significantly lowering energy costs. When specifying an ERV, there are several factors that can help determine the optimal unit for the application. Functional and performance features are important, but considerations for installation, maintenance, and even long-term durability should not be overlooked.
A primary reason for installing an ERV is to recover energy when there is a fresh air requirement for a building. As fresh air is brought into a building, the conditioned air is exhausted back outside to equalize the building’s air pressure. The air leaving a building has energy in it — warm energy in the winter and cool energy in the summer. An ERV can capture 70 percent or more of the energy from the air leaving the building and transfer it to the fresh air entering the building. This capturing of energy means a rooftop HVAC unit does not have to work as hard, which can result in lower utility bills. The rooftop unit can also be sized smaller since the ERV shares the workload.