HVAC Filter Sizing Calculator

Determine the filter face area and quantity needed for an HVAC system based on airflow and maximum face velocity.

CFM
ft/min
in
in

Filters Needed

2

Min Filter Face Area4.00 sq ft
Actual Face Velocity173 ft/min

Filters Needed vs System Airflow

सूत्र देखें →

सूत्र

## Filter Sizing **Face Area = CFM / Face Velocity** **Filters = Face Area / Single Filter Area** Keeping face velocity under 300 ft/min ensures good filtration and low pressure drop. Higher velocities reduce filter life and may blow dust through the media.

हल किया गया उदाहरण

1,200 CFM system, 300 ft/min max, using 20x25 inch filters.

  1. 01Min face area = 1200 / 300 = 4.0 sq ft
  2. 02Filter area = 20 x 25 / 144 = 3.47 sq ft
  3. 03Filters = ceil(4.0 / 3.47) = 2
  4. 04Actual velocity = 1200 / (2 x 3.47) = 173 ft/min