What is HEPA? H13 and H14 grades explained
In one line: HEPA is a filter standard defined by how much it captures at the hardest-to-catch particle size (~0.3 microns). H13 captures ≥99.95%; H14 captures ≥99.995%. Both are "true HEPA"; the higher grades are cleanroom-level and rarely necessary at home.
What HEPA actually means
HEPA stands for High-Efficiency Particulate Air. It isn't a brand — it's a performance standard. A filter earns a HEPA grade by capturing a defined percentage of particles at the "most penetrating particle size" (around 0.3 microns), which is the size hardest for any filter to trap. Capture is actually higher for particles both larger and smaller than that, so the 0.3-micron figure is a worst-case benchmark.
The grades
| Grade | Min. capture @ 0.3µm | Typical use |
|---|---|---|
| H11 | ≥95% | General filtration (not "true HEPA") |
| H12 | ≥99.5% | Better general (still sub-HEPA in EN1822) |
| H13 | ≥99.95% | The usual "true HEPA" for homes/medical |
| H14 | ≥99.995% | Cleanrooms, labs, operating theatres |
Grades below H13 (H10–H12) are sometimes marketed as "HEPA-type" or "HEPA-like" — that is not certified true HEPA and can let noticeably more through. If HEPA matters to you, look specifically for H13 or above.
Do you need HEPA at home?
For a home dealing with dust, pollen, pet dander, smoke and everyday PM2.5, the difference between H13 (99.95%) and a good MERV-13 filter (~90%+) is small in practice — and MERV-13's much lower airflow resistance means the fan moves far more air, giving a higher CADR at lower noise and cost. In other words, the filter grade is only half the story: what cleans your room is clean-air delivery, not the headline capture percentage. H14 is genuine overkill outside cleanrooms and hospitals.
Next step
Weighing HEPA against MERV-13 for a real room? Read HEPA vs MERV-13, or compare units on measured performance at Best Air Purifier UK.
FAQ
Is H14 better than H13 for a bedroom? Marginally, on paper — but H14 restricts airflow more, so you often get cleaner air overall from a lower-grade filter that moves more air. H13 is plenty for a home.
Does HEPA remove smells or gases? No. HEPA captures particles, not gases or odours — for those you need activated carbon.