Part 1: The More "High-Efficiency" a Filter Is, the Better It Is
Many people immediately ask about H13 or ULPA filters. In reality, these are completely unnecessary for most commercial or industrial ventilation systems. Primary and secondary filters are the first line of defense, truly responsible for "blocking large particles." This is especially true in return air and HVAC pre-conditioning sections. Beyond cost, too dense a high-efficiency filter can increase air resistance, impacting system efficiency and ultimately outweighing the benefits.
Part 2: How do primary and secondary filters actually differ?
In short:
Primary filters (G3-G4) block dust, hair, and pollen and are commonly found in office buildings and at the inlets of fresh air systems.
Second-Efficiency filters (M5, M6, F5, F9) filter finer dust and suspended particles and are used in areas like the front end of precision equipment and in workshop air outlets.
If you see terms like "plate," "bag," or "box," don't be confused; these are simply structural differences; the principle remains the same: filter fibers "block" impurities from the air.
Part 3: How to Choose a Reliable Filter? Besides the filtration level, three key factors are essential:
Low wind resistance (initial resistance): Otherwise, your electricity bill will skyrocket.
Large dust holding capacity and long lifespan: Reduce replacement frequency and labor costs.
Stable structure, no fiber shedding, no air leakage: Many low-priced products lack this.
We've been making filters for over 20 years. Honestly, while the appearance is similar, the difference lies in the materials and craftsmanship.