A primary air filter is an air filtration component used in HVAC systems and air handling units (AHUs) to remove larger particles and contaminants from the incoming air. It is the first line of defense in the filtration process and helps protect downstream components, such as secondary filters and the HVAC system itself, from excessive dirt and debris buildup.

The primary air filter is typically a coarse filter designed to capture larger particles like dust, pollen, fibers, and lint. It is commonly made of materials such as fiberglass, synthetic fibers, or polyester. Primary filters are often referred to as pre-filters or coarse filters because they pre-screen the air before it passes through finer filters with higher filtration efficiency.

Primary air filters are classified based on their efficiency and particulate removal capabilities.

The primary air filter is usually located at the point of air intake in an HVAC system or AHU. It is designed to be easily accessible for regular inspection, cleaning, or replacement. The frequency of maintenance depends on factors such as the level of airborne contaminants, the environment, and the specific requirements of the system.

Proper maintenance of primary air filters is important to ensure optimal airflow and efficiency of the HVAC system. Clogged or dirty filters can restrict airflow, reduce system performance, and increase energy consumption. Regular filter inspections and replacements are recommended to maintain good indoor air quality and prolong the life of downstream filtration components.

Primary Z-LINE FILTER (EN779)


Filter Class; G3 – G4

Media; Polyester

Frame type; Galvanized Metal

Standard depth; 48 – 96mm

Final Pressure Drop; 250 Pa

Max. Operating Temperature; 75°C

Application; Prefilter for HVAC

Additional Info:

  • Grid on both sides
  • %100 hot deep galvanized frame
  • High dust holding capacity