Klingenburg enthalpy heat exchangers and sorption exchangers allow both heat energy components to be recovered.

Enthalpy heat exchangers feature a special capillary surface, i.e. one that traps moisture, on the rotor matrix. This ensures that a proportion of the humidity in the air leaving a ventilated room does not pass to the outside but is instead fed back into the room with the supply air. This allows the room humidity level to be maintained.

A sorption heat exchanger can transfer even more moisture. The Klingenburg HUgo sorption rotor has a zeolite coating with particle sizes in the order of nanometres. Water vapour in the exhaust air condenses onto these particles and is then fed back into the supply air.