Xiaomi Smart Air Purifier 4 Compact review
A small-footprint purifier with considerably more capability than its size suggests, combining 230m³/h CADR, smart controls and a very quiet sleep mode.
£69.99 direct from Amazon UK at time of writing
Our verdict
Our Best Compact Smart pick. The 4 Compact offers app control, a PM2.5 sensor and 230 m³/h CADR in a body small enough for a desk, which is an unusual combination at this size.
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Who it suits
- Desks, studies and smaller bedrooms
- Buyers who want smart control in the smallest sensible machine
- People wanting low power draw
- Rooms of roughly 16–27 m²
Room size and airflow
Xiaomi quotes roughly 16–27 m² under its standard test methodology and up to 48 m² at two air changes per hour. Those are two different questions — the lower range reflects faster, more thorough cleaning, so we would size this to a room at the lower end.
Filtration
A 3-in-1 filter combines pre-filtration, fine particle filtration and activated carbon in a single replaceable cartridge, which keeps the machine small and simplifies maintenance.
Noise and everyday use
The 20 dB sleep mode is quiet enough for a bedside table, and 360-degree intake means it works without being pushed against a wall.
Running and ownership costs
At 27 W maximum, energy use is minimal even running continuously; the 3-in-1 cartridge is the recurring cost.
Full specifications
- CADR
- 230 m³/h (manufacturer stated)
- Effective coverage
- Approximately 16–27 m² (Xiaomi standard test methodology)
- Larger room
- Up to 48 m² at 2 air changes per hour
- Sleep mode
- 20 dB
- Maximum power
- 27 W
- Filtration
- 3-in-1
- Sensor
- PM2.5
- Smart control
- Xiaomi Home app
- Air intake
- 360-degree
- Placement
- Desktop or floor
Specifications as published by the manufacturer. Coverage figures use each manufacturer's own air-change assumptions and are not directly comparable between brands.
Strengths
- 230 m³/h CADR is high for the footprint
- 20 dB sleep mode suits bedside use
- 27 W maximum power keeps running costs low
Considerations
- The 48 m² figure assumes only two air changes per hour
- Not intended for large open-plan spaces
- Filter availability is worth checking before buying
Our view
We recommend the 4 Compact where floor space is genuinely limited but smart features and a real PM2.5 sensor still matter.
Alternatives worth comparing
BEST BUDGET
Coway Airmega 50
Compact, quiet and sensibly priced, the Airmega 50 is an excellent choice for bedrooms, nurseries and smaller home offices where full-size purifier performance is unnecessary.
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BEST FOR BEDROOMS
Blueair Blue Max 3250i
Very quiet at its lowest setting, compact enough for a bedroom and considerably more powerful than many small-room purifiers, with smart monitoring and particle-plus-carbon filtration.
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