Zehnder Comfosystems provide a constant supply of fresh air into indoor spaces. Fresh air is fed into the system via an external wall vent. An optional geothermal heat exchanger uses geothermal energy to pre-temper outside air before it enters the system. The heat recovery ventilation device recovers up to 90% of the energy of the extract air to warm the incoming fresh air, saving on heating costs. The air distribution system then channels the optimally tempered fresh air to individual rooms as needed. The air volume can be adjusted individually for each room.