Ventilation is a technology using natural, or mechanical, methods to let outside air enter rooms, or sealed areas, where clean, safe, and suitable air environments are required. Regular ventilation improves indoor air quality and is good for health. Usually ventilation refers to mechanical ventilation.
The advantages of using Dunli external rotor motor powered fans for ventilation systems: 
1. Compact structure, less space used when compared with traditional fans;
2. Low noise, stable performance, small vibration and high reliability;
3. High efficiency, low power consumption;
4. Tapped speed regulation (AC) and stepless speed regulation (EC) are available for applications;
5. Customized design available, based on through flow of customer’s units/equipment.