Heat recovery ventilation, AKA HRV, mechanical ventilation heat recovery and MVHR, is an energy recovery ventilation system based on either a heat recovery ventilator, heat exchanger, air exchanger or air-to-air heat exchanger. The system uses a s a counter-flow heat exchanger to create a healthy heat exchange between inbound and outbound air flows, delivering fresh air and better climate control as well as reducing energy costs by cutting the amount of heating and cooling a building requires.