How Does HRV / ERV Work

How They Work?

In the heating season, Heat Recov Recovery ventlators (HRV) and Energy Recovery Ventilators (ERV) draw in fresh air from outside. This air is distributed throughout the home by a dedicate-duct system or through the forced-air heating / air conditioning system. At the same time, vents located in moisture-and pollutant-producing room(e.g.,  kitchens, bathrooms, laundry rooms) exhaust an equal amount of stale, humid air to the outside. Sometimes air is drawn directly from the return air of a forced-air heating/air conditioning system.

As the two airstreams pass each other in the unit’s core, the fresh air is tempered with heat recovered from the exhaust air. An ERV will also transfer moisture to the fresh air if this air is drier than the exhaust air, improving comfort in overly dry homes.

when the air-conditioning is turned on in summer,the energy of the cold air discharged from the room is used to pre-cool the hot air outside and then sent to the room,and the indoor cooling loss is decresding.

when heating air conditioning is turned on in winter,the energy of warm air exhausted from the room is used preheat the cold air outside before sending it into the room,the indoor heat loss is decreasing.

In the cooling season, the reverse occurs. Fresh outdoor air is cooled by the air-conditioned exhaust air. If the outgoing air is drier than the fresh air, the ERV will transfer moisture to the outgoing air. This process reduces the humidity load on the air conditioning system, which would otherwise result in the continuous introduction of humid summer air to the home.