H11, H13 and H14 Filters: Grades, Airflow and Buying Checks

A higher filter grade describes particle-capture performance under specified test conditions. It does not, by itself, tell you how clean a room will be, how loud the equipment will run or how often its filter needs replacing.

Is H11 really HEPA?

In EN 1822 classification, E10, E11 and E12 are EPA classes; H13 and H14 are HEPA classes. “H11” still appears in product descriptions, so ask which standard and edition the seller means.

MPPS means the most penetrating particle size for the tested filter. It is not simply a claim about all particles above 0.3 micrometres. Camfil’s classification guide describes the classes and test basis.

At those integral thresholds, H14 permits one-tenth the penetration of H13 under the test conditions. That is not ten times cleaner room air: airflow, leakage around the filter, indoor sources and outdoor infiltration also affect the result.

Compare the complete device

For a recirculating room purifier, compare clean-air delivery at a speed you can use comfortably. A highly efficient filter with very low airflow may clean a room slowly. For an outdoor-air supply system, check filtration and delivered airflow together.

Do not infer a fixed pressure drop, energy penalty or service life from the grade alone. Filter area, pleat design, media and operating flow matter. Request the performance data for the actual filter and device.

Five checks before buying a replacement

• Confirm the specified class and applicable test standard.
• Ask for the relevant test report and how it identifies the supplied product.
• Check dimensions, gasket and housing compatibility; matching outer dimensions alone does not prove a good seal.
• Confirm the airflow and pressure conditions used for the rating.
• Follow the equipment maker’s replacement procedure and interval.

Holding a filter up to daylight or judging its colour cannot establish HEPA grade. See the filter-inspection guide for the limits of visual checks.

Which grade does aqi0 use?

aqi0 specifies H13 HEPA in its standalone whole-home air purifier. Its annual care plan includes filter replacement and machine cleaning approximately every 45 days through October–February, with other visits based on pollution load. One of three H13 panels is replaced on rotation per scheduled visit; this is not a universal 6–12 month HEPA lifespan.

See filter care and the technical note for the actual service and performance terms. Specialised clinical or cleanroom requirements should be assessed against the applicable standards by the responsible designer, rather than selected from a residential buying guide.

FAQ

Is “True HEPA” the same as H13?

Sometimes. The term “True HEPA” is loosely used. The US definition typically refers to ≥99.97% at 0.3 µm — which is close to but not identical with EN 1822 H13. Read the specific spec.

Does HEPA capture viruses?

Most viruses are 20–300 nm — smaller than the MPPS. Pure virus particles are captured at higher efficiency than the rated MPPS efficiency. In practice, viruses travel in respiratory droplets (1–10 µm) which HEPA captures at very high efficiency.

Does my AC have a HEPA filter?

No. Standard split and window ACs have a dust filter (G3–G4 in the EN ISO 16890 grading) that captures large particles only. AC air still contains all the PM2.5 of the room air.

How often should I replace the HEPA filter?

Depends on usage and pollution load. For aqi0 systems in NCR: typically 6–12 months. Some installations in very high-load areas need 4–6 months. Visible darkening + measurable airflow drop are the practical indicators.

Is H14 better for COVID protection?

The marginal benefit over H13 for pathogen capture is small. Other factors (ventilation rate, mask use, vaccination) matter more. H13 is generally sufficient.