Heat recovery ventilator, also known as HRV, mechanical ventilation heat recovery, or MVHR, is an energy recovery ventilation system using equipment known as a heat recovery ventilator, heat exchanger, air exchanger, or air-to-air heat exchanger which employs a counter-flow heat exchanger (countercurrent heat exchange) between the inbound and outbound air flow. Heat recovery ventilator provides fresh air and improved climate control, while also saving energy by reducing heating (and cooling) requirements.
Energy recovery ventilator (ERV) are closely related, however ERVs also transfer the humidity level of the exhaust air to the intake air.