Details come from the older review, the maker’s claims and the Amazon listing, checked on October 14, 2026. The old link opened a replacement filter, so the purifier link was fixed. Coverage, power and warranty figures come from the older review and were not retested.
The KOIOS is a cheap, quiet HEPA purifier for a bedroom or an office. Here is what it does, where it falls short and what to compare.
Table of Contents
What You Get
Price on Amazon: $48.87 | 4.5 stars from 6,422 ratings (checked October 14, 2026)
What You Get
The KOIOS is a small, round purifier with a 3-in-1 filter, one button and a night light. The older review said it is easy to use, is ozone free and uses no ions or UV. Power is about 8 watts, and only 0.5 watts on standby. It has two fan speeds and a 3-year warranty with 24/7 customer service and a one-month money-back offer. The box includes the unit, an AC adapter, a carbon filter and a true HEPA filter.
Looking ahead, small HEPA purifiers like the KOIOS are getting cheaper every year. A true HEPA unit for $50 was rare a few years ago, and now it is routine. The catch is that the same price sells a very small machine, and one wrong click can send you to a replacement filter instead of the purifier. The old link on this page now opens a $22.99 filter.
What the Older Review Said
- Coverage. Rooms up to about 215 square feet.
- Filter. A pre-filter, true HEPA and activated carbon, rated to catch 99.97 percent of particles at 0.3 microns.
- Noise. Quiet. The listing says under 25 dB in quiet mode.
- Price. Under $60 in the older review, $48.87 now.
- Downsides. The light cannot be turned off, and the older page was unclear on whether there is a filter-change warning.
- Fit. Not for very large rooms or open-concept spaces, and no Wi-Fi.
The risk to watch is the room size. The older review said the KOIOS cleans rooms up to about 215 square feet, and that is a best case for a small fan. In a bigger room it will barely move the air, and a low-cost buyer may think the unit is broken. Expect more tiny units sold for bedrooms and desks. Check the CADR, keep the room small and plan to replace the filter about every six months.
Care and Filters
Replace the filter about every six months, or sooner in a smoky or dusty home. The listing for the replacement filter is separate from the purifier, which is why the old link on this page now opens a $22.99 filter. Always click through to the unit before you pay. Read how to choose the right size air purifier to match a unit to your room, and see air purifiers for a bedroom for quiet picks.
KOIOS vs Other Small Purifiers
The Levoit Core Mini-P is the better known small unit. For a bigger room, see our Levoit Core 300 review. For more low-cost choices, read most affordable air purifiers and air purifiers for a dorm room.
Prices and Alternatives on Amazon
Prices and ratings were checked on Amazon on October 14, 2026.
Price on Amazon: $48.87 | 4.5 stars from 6,422 ratings (checked October 14, 2026)
The KOIOS H13 is listed with a 3-stage filter (pre-filter, true HEPA and activated carbon), 360 degree air intake and a quiet mode under 25 dB. It has a 4.5 rating from over 6,400 ratings.
Price on Amazon: $43.98 | 4.6 stars from 45,912 ratings (checked October 14, 2026)
The Levoit Core Mini-P is a small purifier for desks, dorm rooms and bedrooms. It has a 4.6 rating from over 45,000 ratings.
Price on Amazon: $89.99 | 4.7 stars from 109,026 ratings (checked October 14, 2026)
The Levoit Core 300-P is listed with a CADR of 143 for smoke, 153 for dust and 167 for pollen. It has a 4.7 rating from over 109,000 ratings.
Price on Amazon: $99.99 | 4.6 stars from 7,662 ratings (checked October 14, 2026)
The Blueair Blue Pure 411 is a small-room purifier with two washable pre-filters. It has a 4.6 rating from over 7,600 ratings.
Pros and Cons
Pros: true HEPA filter; three-stage filtration; quiet mode under 25 dB; low price; small and light; night light; 3-year warranty.
Cons: small coverage, about 215 square feet; light cannot be turned off; no Wi-Fi or air quality monitor; filters are a yearly cost; old link pointed to a filter.
FAQ
How big a room does the KOIOS air purifier cover?
About 215 square feet, per the older review. Use it in a small bedroom or an office.
How loud is it?
The listing says under 25 dB in quiet mode.
How often should you change the filter?
About every six months, per the replacement filter listing.
Does it make ozone?
The older review said it is ozone free and uses no ions or UV.
Final Word
The KOIOS is a good low-cost HEPA unit for a small room. For a bigger room or a better track record, the Levoit units are worth a look.
What happens next: expect more cheap HEPA units with USB power, night lights and filter-change reminders. They suit a bedroom or a desk. For a living room, step up to a larger unit.
Related Guides
Keep going with air purifiers for a dorm room, air purifiers for a bedroom, Levoit Core 300 review, most affordable air purifiers and how to choose the right size air purifier.
