Warm stale air is extracted from the room, then it pass through the ceramic energy accumulator and while flow through it, heats and moistens the ceramic accumulator by transferring thermal energy. After a while, as the ceramic heat exchanger gets heated, the ventilator switches to supply mode automatically.

Clean fresh air from outside passes through the ceramic energy accumulator, absorbs moisture and is heated up to the room temperature due to the accumulated heat. When the temperature of the accumulator drops down, the fan switches to extract mode and the cycle is renewed. The ventilator changes its operation mode between supply and extract ventilation every 65 seconds.