1. Blade shape: The shape of the blades has an important impact on the performance of the fan. Usually, the blades are designed in flat or curved shape to improve airflow efficiency and reduce noise.

2. Number of blades: The number of blades affects the impeller's ability to generate airflow and stability. Usually, the more the number of blades, the better the impeller's airflow generation effect.

3. Angle of blades: The angle of blades affects the direction and speed of airflow. A reasonably designed blade angle can improve the efficiency and performance of the ventilator.

4. Blade gap: The gap between the blades needs to be designed appropriately to ensure that the air can pass through the impeller smoothly, avoiding air leakage and energy loss.

5. Impeller diameter: the diameter of the impeller will affect the air volume and exhaust capacity of the ventilator. According to the actual ventilation needs and space size to choose the appropriate diameter of the impeller.

6. Impeller material: the impeller is usually made of metal, plastic or composite material, choosing the right material can improve the durability and performance of the impeller.

7. Dynamic balance: The dynamic balance of the impeller is especially important to ensure that the impeller will not produce vibration or noise when rotating at high speed, so as to improve the stability and service life of the fan.

Through reasonable impeller design, the ventilation efficiency and air flow performance of forced ventilation fan can be improved to ensure that the ventilation system can effectively realize the function of ventilation, air exchange or air exhaust.