The new heat recovery units are distinguished by twin heat recovery system for transferring the energy otherwise lost when extracting air from the room: the first system, static type, by aluminium plated crossflow heat recovery, the second system (in sequence to the previous one) by electric driven air-to-air R410A heat pump device. Therefore, by a single independent system and at the same time, it can match the needing of ventilation while ensuring room comfort, the outside air thermal loads and the energy saving, due to the very high unit efficiency, both on winter and summer time.