According to the actual applications and new requirements from our customers, Holtop developed a new version of wall-mounted ERV energy recovery ventilation unit, the CO2 version wall-mounted ERV. It is different from our PM2.5 version wall-mounted ERV. Now the wall-mounted ERV can be equipped with either a CO2 sensor or a PM2.5 sensor. Their working logic is different when the ERV is under Auto Mode. Users can select the version depends on the actual project needs. When the room is crowded, the CO2 concentration is higher than the normal situation, then the CO2 sensor will detect the CO2 concentration value, and the ERV will run at high speed automatically.