The short version: HEPA captures a fraction more of the very smallest particles; MERV-13 captures the fine PM2.5 that drives health harm while letting a fan move far more air. For a home, throughput usually wins — cleaner air overall, at lower cost.
| MERV-13 | HEPA (H13) | |
|---|---|---|
| Captures PM2.5 | Yes (~93%+ typical) | Yes (99.95% at 0.3µm) |
| Airflow resistance | Low — high CADR | High — chokes airflow |
| Filter cost | Low, standard sizes | Higher, often proprietary |
| Best for | Whole-room clean air | Sealed medical/lab settings |
Ready to clean up your London air?
Luggable MERV-13 kits deliver up to 681 m³/h CADR — built on the Corsi-Rosenthal principle, from £229. Ships from Oxford in 2–3 days.
Shop the UK store → See all kitsWhy airflow wins at home
Clean-air delivery = filter efficiency × airflow. A HEPA unit that filters 99.95% but only moves 200 m³/h can be beaten by a MERV-13 kit moving 600 m³/h, because the MERV-13 kit simply processes far more of the room's air each hour. That's why the Corsi-Rosenthal box — pure MERV-13 airflow — punches so far above its price.
Frequently asked questions
Is MERV-13 good enough for PM2.5?
Yes. MERV-13 captures the great majority of PM2.5, and because it allows high airflow it clears a whole room quickly — the metric that matters for home air.
When is HEPA actually better?
In sealed settings where you need to capture the very smallest particles at all costs and airflow is secondary — labs, clean rooms, some medical uses.