G4 Filters

About G4 Filters

G4 filters are part of the former EN 779 classification system and are widely recognized as coarse pre-filters for HVAC and industrial air handling systems. They are typically used to remove larger airborne particles before air passes to finer filtration stages.

Although EN 779 has been replaced by ISO 16890, G4 remains a commonly used reference term in maintenance, replacement, and distributor markets. For many applications, G4 filters serve as an economical first filtration stage that helps reduce dust loading on downstream filters and supports more stable system operation.

Typical Applications

G4 filters are commonly used in:

• commercial HVAC systems
• industrial ventilation systems
• air handling units
• manufacturing facilities
• pre-filtration stages in multi-stage systems
• general building ventilation

Key Features

• coarse particle removal
• low initial pressure drop
• cost-effective pre-filtration
• protection for downstream fine filters
• suitable for large dust particles and fibers
• widely used in replacement markets

G4 Filters and ISO 16890

G4 is a legacy EN 779 filter grade. Under the modern ISO 16890 framework, G4 filters are commonly associated with ISO Coarse performance, depending on actual product design and test results.

Because EN 779 and ISO 16890 use different test methods, G4 should not be treated as an exact one-to-one ISO equivalent. However, it is broadly understood as a coarse pre-filtration grade.

Selection Considerations

G4 filters are typically selected when the main objective is to remove larger airborne particles while maintaining low resistance and economical operation. They are most often used as the first filtration stage rather than as final filters in applications requiring higher indoor air quality.

FAQ

What is a G4 filter?

A G4 filter is a legacy EN 779 coarse air filter grade commonly used for pre-filtration in HVAC and industrial ventilation systems.

Are G4 filters still used?

Yes. G4 remains widely used as a legacy reference term in replacement and maintenance markets, even though EN 779 has been replaced by ISO 16890.

What is the ISO equivalent of G4?

G4 filters are generally associated with ISO Coarse performance, but the exact relationship depends on product testing and design.

Are G4 filters suitable as final filters?

In most cases, no. They are mainly used as pre-filters before finer filtration stages.