The size of an inline fan that you need will depend on several factors, including the size of the room or space you are trying to ventilate, the desired air exchange rate, and the resistance to airflow caused by any ductwork or other components in the ventilation system.
To calculate the size of the inline fan you need, you can follow these general steps:
Determine the volume of the space you want to ventilate. You can do this by multiplying the length, width, and height of the space in feet.
Determine the desired air exchange rate. This is the number of times you want the air in the space to be exchanged with fresh air per hour. A typical air exchange rate for a residential bathroom is 8-10 times per hour, while a kitchen may require 15-20 times per hour.
Calculate the required airflow rate. Calculating the cubic meters per hour (m³/h) of ventilation required depends on the volume of the space that needs ventilation and the number of air changes per hour (ACH) desired. The ACH is the number of times the volume of air in the room is replaced in an hour.
Here's the formula:
Ventilation (m³/h) = Volume of space (m³) x ACH
To calculate the volume of space, multiply the length, width, and height of the room in meters. For example, if a room is 5 meters long, 4 meters wide, and 3 meters high, the volume of the space is 5 x 4 x 3 = 60 m³.
Consider the resistance to airflow. If you have long duct runs or other components that may impede airflow, you may need to choose a larger fan to compensate.
Choose a fan that can deliver the required airflow rate. You can find this information in the fan's specifications. Look for the fan's airflow rating in cubic feet per minute (m³/h) and choose a fan that can deliver the required m³/h.