Micra 100 WiFi units are equipped with a counter-flow heat exchanger with a polystyrene core. In the cold season the extract air heat is captured and transferred to the supply air stream, which reduces the ventilation-generated heat losses. However, this process may be associated with condensation, which is collected in a special drain pan and evacuated outside via the exhaust air duct. In the warm season the ambient air heat is transferred to the exhaust air stream.