Heat Pump Heat Recovery Ventilation Units with heat pump, designed for saving energy and also improving indoor air quality. VHR DX Units provide heat recovery and well conditioned fresh air by air to air plate type exchangers and heat pump. 30oC fresh air in the summer time and 12oC fresh air in the winter time can be obtained by usual heat recovery units, but these results are not comfortable. You can obtain 20oC fresh air in the winter time with high efficiency heat pump.