Air Purifiers That Kill Viruses and Bacteria vs Ones That Just Trap Them

Trapping and killing are two different jobs

Walk through any electronics floor in Singapore and you will see box after box claiming to "kill 99.9% of germs". Lines like that usually describe removal: the machine pulled microbes out of the air and lodged them in a filter. Nothing on an ordinary filter kills anything.

Filtration itself is genuinely effective. H13 is defined under EN 1822 as capturing at least 99.95% of particles at the most-penetrating particle size, and every AIRE room purifier uses H13 medical-grade HEPA as standard — capturing at least 99.95% of particles down to 0.1 micron. Viruses and bacteria travelling on droplets and dust are caught efficiently.

But captured is not the same as dead. A trap-only purifier moves live microbes from the air you breathe onto a surface inside the machine. That distinction is the whole point of this article.

What happens to germs on an ordinary HEPA filter

A HEPA filter has no killing mechanism of its own. Microbes caught in the fibres simply sit there and decay in their own time.

We measured this in chamber testing. On a standard HEPA filter, the tested organisms — E. coli, Staphylococcus albus and Influenza A — took roughly 4 hours 23 minutes to decay passively. For over four hours, the filter is effectively a holding surface for viable bacteria and viruses, with air flowing continuously across it.

That matters most in exactly the places purifiers are bought for hygiene: clinics, childcare centres and homes with vulnerable occupants. It is also a reason to handle used filters from trap-only units with care. We unpack the mechanics further in Do HEPA filters kill viruses?

How active sterilisation kills what the filter catches

This is the gap active sterilisation closes. AIRE pairs H13 filtration with active sterilisation — UV-C light plus copper-silver ion technology — which eliminated more than 99.99% of tested airborne pathogens (E. coli, Staphylococcus albus, Influenza A) within 60 minutes in chamber testing, versus roughly 4 hours 23 minutes for the same organisms to decay passively on a standard HEPA filter.

Same organisms, same chamber: 60 minutes with active sterilisation against more than four hours without it. That is the difference between a purifier that stores germs and one that neutralises them.

The full stack in our room units runs seven layers: aluminium pre-filter, cold catalyst, activated carbon, antibacterial layer, H13 HEPA, UV-C sterilisation and anion release. The UV-C lamp sits inside a sealed chamber, so it works on the filter and airstream without ever reaching the people in the room — more on that in our UV-C safety explainer. The full breakdown is on our technology page.

Trap-only vs trap-and-kill at a glance

Here is the comparison stripped to what actually changes for you.

How to vet any "kills 99.9%" claim — including ours

Whichever brand you are weighing up, apply the same test. A percentage with no time frame, organism list or method behind it is a marketing line, not evidence.

1. Which organisms were tested? Ours are named: E. coli, Staphylococcus albus and Influenza A. Be wary of claims that name none at all.
2. How fast? "Kills 99.9%" over a day and over 60 minutes are very different machines. Ask for the kill time.
3. Air removal or true kill? Ask whether the figure measures microbes removed from the air or microbes neutralised on the filter itself.
4. Under what conditions? Controlled chamber testing is the standard — ask to see it.
5. Is the device certified? AIRE holds FDA Class 2 medical device listing plus CE and RoHS compliance, and is certified to ISO 9001 and ISO 14001.

One honest boundary: no purifier — ours included — can promise you will not fall ill. What a trap-and-kill unit does is reduce the airborne load of viruses and bacteria, help lower your exposure, and support your wider infection-control habits.

Choosing a unit that traps and kills — sized for your room

Killing power only counts if the unit also turns the room's air over fast enough. Public-health guidance since the pandemic (including the US CDC) recommends targeting at least 5 air changes per hour of clean air in occupied spaces; as a working rule we size for 3–4 ACH in homes, 4–5 in offices and 5 or more in clinics.

The maths is simple: required CADR (m³/h) = floor area (m²) × ceiling height (m) × target air changes per hour. Or let our size calculator do it for you.

• Fillo Plus — up to 30 m², CADR 300 m³/h. Bedrooms, small offices, consult and treatment rooms.
• Classic 400S — 31–54 m², CADR 480 m³/h. Living rooms, offices and clinic waiting rooms.
• Pro 800S — 56–96 m², CADR 800 m³/h. Halls, gyms and large clinics.

All three pair H13 medical-grade HEPA with the same UV-C and copper-silver ion sterilisation. Browse the range on our products page, or start a free 30-day pilot — zero upfront cost, and at the end you buy, rent or return. We are a Singapore brand based in Geylang, and we install and support every unit locally.

Frequently asked

Do HEPA filters kill viruses and bacteria?

No. An H13 HEPA filter captures at least 99.95% of particles at the most-penetrating particle size (the EN 1822 standard), but it has no mechanism to kill what it catches. In our chamber testing, the tested organisms took roughly 4 hours 23 minutes to decay passively on a standard HEPA filter.

Is the UV-C light inside an air purifier safe to be around?

Yes, when it is properly enclosed. The UV-C lamp in AIRE units sits inside a sealed chamber, so the light sterilises the filter and airstream without reaching anyone in the room. That is what allows the units to run continuously in occupied spaces such as bedrooms, clinics and childcare centres.

Will an air purifier stop me catching the flu?

No purifier can promise that, and you should be cautious of any brand that does. A unit with active sterilisation reduces the airborne load of viruses and bacteria in the room, which helps lower your exposure. Treat it as one layer of infection control alongside ventilation and good hygiene, not a shield.

What should I ask before trusting a "kills 99.9%" claim?

Ask for the named organisms, the kill time and the test method. In our case that is more than 99.99% of tested pathogens — E. coli, Staphylococcus albus and Influenza A — eliminated within 60 minutes in chamber testing. A percentage with no time frame or organism list tells you very little.

Related reading

• Do HEPA Filters Kill Viruses or Just Trap Them?
• Air Purifier vs Air Steriliser: What's the Difference?
• Medical-Grade vs Consumer Air Purifiers: The Real Difference