Levoit Core 300
AHAM verified
- Really cleans
- 217 sq ft20 m² 20 m²217 sq ft
- Box says
- 1,066 sq ft99 m² 4.9× overstated
- New filter
- 6–8 months
Xiaomi · AC-M18-SC
Xiaomi Smart Air Purifier 4 Compact
Not verified. A verified model that cleans at least as much: Levoit Core 300, 217 sq ft20 m².
Really cleansNot verified
206 sq ft19 m² 19 m²206 sq ft
At 4.8 air changes an hour with a 2.5 m ceiling
- Box says
- It can purify a 48 m² room 2 times per hour (517 sq ft)It can purify a 48 m² room 2 times per hour 2.5× overstated
- New filter
- Every 6–12 months
A small Xiaomi cylinder sold widely in Europe. Its CADR is Xiaomi's own particle figure to a Chinese standard, not AHAM smoke CADR.
Verdict
Who it's for
Xiaomi rates it with a particle CADR under China's GB/T 18801 standard, not AHAM's smoke test, so we treat it as unverified. Xiaomi's own spec sheet gives a much smaller room size than its headline, closer to our maths. A reasonable bedroom unit if you accept the maker's figure.
Good
- PM2.5 laser sensor and app control
- No ionizer
- Small and light
Trade-offs
- CADR is a maker figure to a different standard
- Headline room size assumes two air changes an hour
Spec facts
Xiaomi Smart Air Purifier 4 Compact · AC-M18-SC
- Really cleans
- 206 sq ft · 19 m²19 m² · 206 sq ftat 4.8 air changes an hour, 2.5 m ceiling
- Smoke CADR
- 230 m³/h · 135 CFMMaker’s figure, not independently verified
- Maker’s claim: Xiaomi · checked 1 Nov 2026
- Box claim
- It can purify a 48 m² room 2 times per hour (517 sq ft)It can purify a 48 m² room 2 times per hour2.5× overstated
- Maker’s claim: Xiaomi · checked 1 Nov 2026
- Filter
- Xiaomi Smart Air Purifier 4 Compact Filter3-in-1: primary filter, high-efficiency filter, activated carbon. Replace every 6–12 months
- Maker’s claim: Xiaomi · checked 1 Nov 2026
Maker’s claim: the manufacturer’s own figure, not independently checked. Where figures come from
Running it
Filter and upkeep
- Replacement filter
- Xiaomi Smart Air Purifier 4 Compact Filter
- Type
- 3-in-1: primary filter, high-efficiency filter, activated carbon
- Replace every
- 6–12 months
- Power at top speed
- 27 W
A new filter every 6–12 months means 1–2 filters a year. At top speed it draws 27 W: 0.6 kWh if it ran flat out all day. Slower settings use less.
We have no Amazon link for this filter: the maker's page in the sources sells or lists it.
Source: Maker’s claim, Xiaomi, checked 1 Nov 2026
The box vs the maths
The box says 517 sq ft48 m². It really cleans 206 sq ft19 m².
To clean 517 sq ft48 m² it would only change the air in the room 1.9 times an hour. We size every purifier at 4.8 air changes an hour, the level AHAM's room-size guideline works out to.
Xiaomi sizes it at about 2 times an hour, and says so: better than the once an hour many makers use, but well short of 4.8. The CADR behind both numbers is Xiaomi's own; AHAM hasn't certified it.
230 m³/h smoke CADR ÷ (4.8 × 2.5 m ceiling) = 19.2 m² = 206.3 sq ft19.2 m²
Use the calculator for your exact room and ceiling, or read how we pick.
Drawn to scale: the box says “It can purify a 48 m² room 2 times per hour”, the purifier really cleans 206 sq ft, 2.5 times less.Drawn to scale: the box says “It can purify a 48 m² room 2 times per hour”, the purifier really cleans 19 m², 2.5 times less.
Room sizes
Which rooms it fits
It suits 107 sq ft10 m² and 161 sq ft15 m² rooms best: there it has 26–90% more air than the room needs, so it needn't run flat out.
Under a 2.7 m ceiling it covers 191 sq ft, under 3 m 171 sq ftUnder a 2.7 m ceiling it covers 17 m², under 3 m 15 m²: still enough for every size it covers above (why).
For a 215 sq ft room or bigger it's too small, although the box claims 517 sq ft: the For a 20 m² room or bigger it's too small, although the box claims 48 m²: the 215 sq ft20 m² page lists models that cover it.
All of this rests on Xiaomi's own CADR figure. AHAM hasn't certified it, so we never make it a pick; a certified model is the safer buy at the same size.
Room pages it qualifies for
Alternatives
The Xiaomi Smart Air Purifier 4 Compact or one of these?
The certified models closest in size, and what is different about each, from the same kinds of source.
Cleans 217 sq ft, 11 sq ft moreCleans 20 m², 1 m² more, on a certified CADR. It has no air quality sensor. It needs filters more often (every 6–8 months) and draws 56 W at top speed. 1.4 kg heavier.
Levoit Vital 100S-P
AHAM verified
- Really cleans
- 217 sq ft20 m² 20 m²217 sq ft
- Box says
- 1,066 sq ft99 m² 4.9× overstated
- New filter
- 6–12 months
Cleans 217 sq ft, 11 sq ft moreCleans 20 m², 1 m² more, on a certified CADR. Same sensor, ionizer and filter interval. 5.1 cm taller and 1.7 kg heavier.
Blueair Blue Pure 511i Max
AHAM verified
- Really cleans
- 233 sq ft21 m² 21 m²233 sq ft
- Box says
- 1,138 sq ft106 m² 4.9× overstated
- New filter
- 9 months
Cleans 233 sq ft, 27 sq ft moreCleans 21 m², 2 m² more, on a certified CADR. It has a different filter schedule (every 9 months) and draws 17 W at top speed.
Sources
Where these numbers come from
- Maker’s claim Xiaomi Smart Air Purifier 4 Compact overview · Xiaomi
- Maker’s claim Xiaomi Smart Air Purifier 4 Compact specifications · Xiaomi
We don't test purifiers ourselves: every figure on this page is copied from these sources and was last checked on 1 Nov 2026. Spotted one that's wrong or out of date? Tell us and we'll fix it and change the date.