Filter Classes Table 2025: Selecting G4, F7, HEPA Filters Correctly
Whether indoor cannabis cultivation, cleanroom technology, office ventilation systems, or highly sensitive laboratories: The right filter class determines whether your air remains free of mold spores, fine dust, and pathogens – and whether your equipment operates trouble-free long-term. Many operators know terms like G4 filters, F7 filters, or HEPA filter classes, but often lack an overview of the current filter classes table according to ISO 16890 and EN 1822.
This comprehensive guide explains all important filter classes from G3 to UHEPA, shows the differences between old and new standards, and helps you find the optimal filter combination for your application. With practical calculation examples, cost analyses, and maintenance tips, you’ll become an expert in professional air filtration.
Why a Current Filter Classes Table is Essential
Since 2018, the ISO 16890 standard has replaced the old EU-G/M/F system (EN 779) for coarse and fine dust filters. Parallel to this, EN 1822 continues to regulate HEPA filter classes H10 to H14 and the even stricter UHEPA classes. Modern concepts for ventilation filter classes combine both regulatory frameworks to ensure comprehensive air purification.
The Revolutionary Changes Through ISO 16890:
The new standard brought fundamental improvements:
More Realistic Testing: Real urban dust mixture is used instead of artificial test dust
Size-Specific Evaluation: Separate values for ePM10, ePM2.5, and ePM1 (Particle Matter of various sizes)
Conditioning Process: Filters are “conditioned” with electrostatically discharged particles before testing
More Practical Application: Direct assignment to health protection categories
The Two Major Standard Families in Detail:
ISO 16890: Defines coarse dust (ePM > 10 µm), fine dust (ePM 2.5), and ultrafine dust (ePM 1.0). In everyday practice, many still speak of G4 filter class, M5 filter, or F7 filter class – what’s crucial is that the new ISO values appear on the nameplate.
EN 1822: Regulates HEPA filter classes H10 to H14 and UHEPA classes U15-U17. Separation efficiencies range between 85% and 99.9995% for 0.1 µm particles – indispensable against viruses, bacteria, and ultrafine contaminations.
Complete Filter Classes Table 2025 – All Standards at a Glance
| Old Designation | ISO 16890 Class | Separation Efficiency | Particle Size | Pressure Drop (Pa) | Typical Application |
|---|---|---|---|---|---|
| G1 | ISO Coarse > 35% | ≥ 35% | > 10 µm | 20-40 | Insect protection, coarse contamination |
| G2 | ISO Coarse > 50% | ≥ 50% | > 5 µm | 25-50 | Outdoor air pre-filtration |
| Filter G3 | ISO Coarse > 60% | ≥ 60% | > 3 µm | 30-60 | Pollen, leaves, large dust particles |
| G4 Filter | ISO Coarse > 90% | ≥ 90% | 1-10 µm | 40-80 | Standard pre-filter, protection of downstream filters |
| M5 Filter | ePM10 50% | ≥ 50% | 1-10 µm | 60-120 | Fine dust, first microorganisms |
| M6 | ePM10 70% | ≥ 70% | 0.5-10 µm | 80-150 | Bacteria, diesel soot, smoke |
| F7 Filter | ePM2.5 65% | ≥ 65% | 0.4-2.5 µm | 100-200 | Mold spores, allergens, office ventilation |
| F8 | ePM1 70% | ≥ 70% | 0.3-1 µm | 150-250 | Microplastics, exhaust fine dust |
| F9 | ePM1 80% | ≥ 80% | 0.2-1 µm | 200-300 | Cleanrooms, medicine, pharmaceuticals |
| H10 | — | ≥ 85% | 0.1 µm (MPPS) | 250-400 | Quarantine, first HEPA stage |
| H11 | — | ≥ 95% | 0.1 µm (MPPS) | 300-500 | Mother plants, laboratory pre-stage |
| H12 | — | ≥ 99.5% | 0.1 µm (MPPS) | 400-600 | GMP areas, sterile production |
| H13 | — | ≥ 99.95% | 0.1 µm (MPPS) | 500-800 | Cleanroom Class B, virus barrier |
| H14 | — | ≥ 99.995% | 0.1 µm (MPPS) | 600-1000 | Highest requirements, medical cannabis |
| U15-U17 | — | ≥ 99.9995% | 0.1 µm (MPPS) | 800-1500 | Ultra-cleanrooms, semiconductor industry |
MPPS = Most Penetrating Particle Size (most difficult particle size to separate)
Optimal Filter Cascades for Various Applications
Successful filter class ventilation concepts rely on at least two, usually three filter stages. The right combination protects expensive downstream filters, optimizes energy efficiency, and ensures the required air quality.
Standard Office Buildings (Comfort Ventilation):
Cascade: G4 Filter Class + F7 Filter Class
- Pre-filter G4: Protects heat exchangers and F7 filters from coarse dust
- Main filter F7: Removes 65% of health-harmful PM2.5 particles
- Air change rate: 2-6 per hour depending on occupancy
- Maintenance interval: G4 every 3-4 months, F7 every 6-12 months
Cannabis Growing Rooms (Grow Ventilation):
Cascade: G4 Filter + F7 Filter + Activated Carbon Filter
For professional indoor grows, leading providers combine various filter technologies. CarbonActive filter solutions offer coordinated systems for this purpose:
- Supply Air Pre-filtration: Pollen filters or pollen socks keep spores and contamination away
- Exhaust Air Purification: Combined filter boxes with activated carbon for odor control
- Air change rate: 20-60 per hour for optimal plant climate
- Special filters: Pre-filters extend main filter lifespan
Medical Cleanrooms (GMP-Compliant Production):
Cascade: G4 Filter + F8/F9 + HEPA Filter Class H13/H14
- Three-stage filtration: Gradual purification to sterility
- Terminal HEPA filters: Directly before critical areas
- Air change rate: 15-30 per hour with laminar flow
- Validation: Regular leak testing and particle counting
Detailed Analysis of Important Filter Classes
G4 Filter – The Robust Workhorse
The G4 filter is the most commonly used pre-filter in professional ventilation systems. With its ability to separate over 90% of particles larger than 1 µm, it forms the foundation of every filter cascade.
Technical Characteristics:
- Filter Medium: Mostly synthetic fibers or glass fiber fleeces
- Construction: Pleated for large filter surface area with compact dimensions
- Initial Pressure Drop: 40-80 Pa at nominal air flow
- Dust Holding Capacity: 200-400 g/m² depending on design
- Temperature Resistance: Up to 158°F (70°C), special variants up to 212°F (100°C)
Application Advantages:
- Cost-effective in acquisition and operation
- Protects expensive downstream filters from clogging
- Extends heat exchanger lifespan
- Easy handling and maintenance
- Regenerable through washing (with suitable media)
F7 Filter – The All-Rounder for Fine Dust
Filter class F7 is considered the optimal compromise between separation performance, energy efficiency, and costs. With 65% separation of critical PM2.5 particles, the F7 filter meets high health protection requirements.
Why F7 Filters are Particularly Effective:
- Target Size PM2.5: Binds respirable particles that are particularly harmful to health
- Electrostatic Effect: Modern F7 filters use charge effects for higher efficiency
- Gradual Separation: Large particles through inertial separation, small ones through diffusion
- Long Service Life: 6-12 months under normal load
F7 Filter Sizing Calculation Example:
Given Values:
- Room volume: 3,531 ft³ (100 m³)
- Desired air changes: 6 per hour
- Air flow: 3,531 ft³ × 6 = 21,186 ft³/h (600 m³/h)
Filter Sizing:
- F7 approach velocity: max. 8.2 ft/s (2.5 m/s) for optimal efficiency
- Required filter area: 21,186 ft³/h ÷ 3600 s/h ÷ 8.2 ft/s = 0.72 ft² (0.067 m²)
- Standard filter 11.3×11.3 in (287×287 mm): 0.88 ft² (0.082 m²) → adequately sized
- Pressure drop: approx. 120 Pa initial, 200 Pa at filter change
HEPA Filter Classes H13 & H14 – Perfection in Air Purification
HEPA filter classes H13 and H14 represent the pinnacle of mechanical air filtration. With separation efficiencies of 99.95% and 99.995% respectively for 0.1 µm particles, they are indispensable for the highest purity requirements.
Construction and Operating Principle:
- Filter Medium: Microfiber glass fleece with defined pore sizes
- Separators: Aluminum pleats ensure uniform airflow
- Frame: Usually wood or plastic with high-temperature sealing
- Testing: Each filter is individually tested and certified
Quality Criteria for HEPA Filters:
- Integrity Testing: DOP test or modern laser photometer methods
- Leakage Rate: Local leaks may not exceed 0.005% (H13) or 0.001% (H14)
- Pressure Resistance: Minimum 1000 Pa differential pressure
- Temperature Class: Standard 158°F (70°C), high-temperature variants up to 482°F (250°C)
ISO 16890 vs. Old EN 779 – Migration and Transition Regulations
The transition from EN 779 to ISO 16890 brought not only new designations but also improved testing procedures. Many dealers still use the old terms – this is permitted as long as ISO values are additionally specified.
Conversion Table EN 779 → ISO 16890:
| EN 779 (old) | ISO 16890 (new) | Remarks |
|---|---|---|
| G3 | ISO Coarse 60% | Direct correspondence |
| G4 | ISO Coarse 90% | Stricter requirements |
| M5 | ePM10 50% | New particle size definition |
| M6 | ePM10 70% | Comparable performance |
| F7 | ePM2.5 65% | Focus on health-relevant PM2.5 |
| F8 | ePM1 70% | Ultrafine particles in focus |
| F9 | ePM1 80% | Highest ISO class before HEPA |
Purchase Recommendations for 2025:
- Complete Labeling: Insist on ISO 16890 certification
- Test Reports: Demand independent test protocols
- Conditioned Values: Pay attention to values after electrostatic discharge
- Annual Energy Consumption: New filters show energy ratings
Practical Filter Sizing and Cost Calculation
Step-by-Step Guide to Filter Selection:
1. Requirements Analysis:
- Which particle sizes must be separated?
- Are there special hygiene requirements?
- How high is the dust load of outdoor air?
- What energy efficiency goals are being pursued?
2. Air Flow Calculation:
- Room volume × desired air change rate per hour
- Plus 10-20% safety margin
- Consideration of leakage air flows
3. Filter Class Determination:
- Coarse/pre-filters according to outdoor air pollution
- Fine filters according to indoor air quality requirements
- HEPA filters only when demonstrably necessary
4. Pressure Drop Calculation:
- Sum of all filter losses
- Plus duct network and components
- Fan selection according to total pressure drop
Life Cycle Cost Calculation (Example):
Office building, 35,314 ft³/h (1000 m³/h), G4+F7 cascade:
| Cost Factor | Annual Costs | 10-Year Costs |
|---|---|---|
| G4 filters (4x/year) | $175 | $1,750 |
| F7 filters (1x/year) | $130 | $1,300 |
| Personnel costs maintenance | $220 | $2,200 |
| Energy costs (150 Pa @ $0.27/kWh) | $310 | $3,100 |
| Total | $835 | $8,350 |
Energy costs dominate over the life cycle – efficient filters pay for themselves!
Maintenance and Monitoring: Maximizing Filter Lifespan
Monitoring Parameters for All Filter Classes:
- Pressure Drop Monitoring: Continuous monitoring with differential pressure meters
- Air Flow Control: Regular measurements with calibrated instruments
- Visual Inspection: Monthly visual check for damage
- Microbiological Controls: For HEPA filters every 6-12 months
Change Criteria by Filter Classes:
G4 Filter:
- Pressure drop reaches 250 Pa
- Visible contamination
- At latest after 6 months
- Immediately in case of mold infestation
F7 Filter:
- Pressure drop exceeds 300 Pa
- Air flow falls below 80% of nominal value
- Maximum 12 months operating time
- Early replacement if odors develop
HEPA Filter Classes:
- Integrity test shows leaks > limit value
- Pressure drop reaches 500-800 Pa depending on class
- After 2-5 years depending on load
- Always after contamination
Avoiding Common Filter Class Mistakes
❌ The 10 Most Common Planning Errors:
- Wrong Filter Sequence: HEPA before coarse filter leads to immediate clogging
- Oversized Approach Velocity: Significantly reduces separation performance
- Underestimated Pressure Drops: Fan sized too weak
- Missing Maintenance Access: Makes filter changes considerably more difficult
- Outdated Standards: EN 779 specified instead of ISO 16890
- Unsuitable Filter Frames: Leak points reduce overall efficiency
- Too Infrequent Maintenance: Overloaded filters lose effectiveness
- Missing Pressure Measurement: Filter condition not monitorable
- Savings in the wrong place: Cheap filters cost more long-term
- No Bypass Control: System shutdown during filter changes
✅ Proven Planning Principles:
- Staged Filtration: Coarse → Fine → HEPA/Active Filters
- Conservative Design: 20% safety margin for pressure drops
- Choose Quality Filters: Prefer certified brand manufacturers
- Maintenance-Friendly Planning: Sufficient space for filter changes
- Implement Monitoring: Automatic condition monitoring
Special Filters and Future Technologies
Activated Carbon Combination Filters:
Modern systems combine mechanical filtration with adsorption. For cannabis grows, manufacturers like CarbonActive offer combined filter solutions that eliminate both particles and odors.
Electrostatic Filters:
- Operating Principle: Electric charge collects particles
- Advantages: Low pressure drop, washable
- Disadvantages: Ozone generation, regular cleaning needed
- Application: Industrial exhaust air, kitchen exhausts
UV-C Combination Filters:
- Additional Benefit: Inactivation of microorganisms
- Application Area: Medical ventilation, food industry
- Maintenance: Replace UV lamps every 8000-12000 operating hours
FAQ: Answers to the Most Important Questions About Filter Classes
What is the difference between F7 filter and Filter F7? None – both terms designate the same filter class F7 according to EN 779 or ISO 16890 ePM2.5 65%. The word order is just a matter of phrasing.
How often should a G4 filter be changed? A G4 filter should be replaced every 3-6 months, depending on dust load and operating hours. With high outdoor air pollution or continuous operation, monthly replacement may be necessary.
Can I operate HEPA filter classes H14 without pre-filters? No, definitely not. Without G4 filters and F7 filters as pre-filters, an H14 HEPA filter clogs within a few days and loses its effectiveness. The filter cascade is essential.
Are HEPA filter classes also relevant for exhaust air? Yes, especially when exhaust air enters neighborhoods or other building parts and must not spread germs, viruses, or odors. In laboratories and medical facilities, HEPA exhaust air filtration is standard.
What does ISO 16890 mean in practice? ISO 16890 makes filter specifications more realistic and comparable. Real urban dust is used instead of artificial test dusts. The ePM values (ePM10, ePM2.5, ePM1) directly show how well filters work against health-harmful particles.
Which filter class do I need for cannabis cultivation? For professional cannabis grows, a combination is recommended: G4 filter for supply air pre-filtration, F7 filter against mold spores, and activated carbon filter for odor control in exhaust air.
How do I recognize outdated filter designations? Outdated products show only EN 779 classes (G1-G4, M5-M6, F7-F9) without ISO 16890 values. Modern filters have both specifications or exclusively the new ePM classifications.
What does a complete filter cascade cost? Costs depend heavily on size and quality. For standard office ventilation (35,314 ft³/h / 1000 m³/h), calculate $325-875 for initial equipment (G4+F7) and $220-435 annual operating costs.
The Right Filter Classes Table as Foundation for Successful Air Purification
From G4 filter class to HEPA filter class H14 – only those who understand the current filter classes table and ISO 16890 requirements can build an efficient, standards-compliant filter cascade. The transition from EN 779 to the new standard brought more realistic testing procedures and better comparability.
The Most Important Insights Summarized:
- Staged Filtration is Indispensable: G4 filters protect expensive downstream filters and system components
- F7 Filters are the Standard: Optimal compromise between efficiency, costs, and health protection
- HEPA Only When Truly Needed: HEPA filter classes H13/H14 for highest purity requirements
- Observe New Standards: ISO 16890 replaces outdated EN 779 classification
- Maintenance is Crucial: Regular filter changes maintain performance and save energy
Whether simple office ventilation, professional cannabis cultivation, or sterile laboratory environment – with the right combination of filter classes and professional planning, you achieve optimally purified air at minimal operating costs. Invest in proven quality from established manufacturers and benefit from reliable air purification that protects your health and keeps your systems operating optimally.
The Filter Classes Table 2025 shows: Modern air filtration is a science in itself – but with the right knowledge, you choose the optimal solution for every application.
