Mijia Smart Air Purifier 4 Compact Review: Is this air purifier perfect for bedrooms and studies?

Summary

The new Mijia Smart Air Purifier 4 Compact is a dependable, budget-friendly workhorse with sophisticated and useful tech. Which room should you use it to clean?

No longer a seasonal inconvenience, air pollution is part of everyday life thanks to year-round construction dust and traffic fumes. The Smart Air Purifier 4 Compact ( ₹7,999) from Xiaomi's Mijia sub-brand arrives in time to make cleaner indoor air accessible without commandeering your living room. it's small, relatively affordable and packs some smarts, but can it punch above its weight to get the job done?

Built for compact spaces

At 35.5cm tall and 22cm wide, the Smart Air Purifier 4 Compact is rather easy to accommodate, and its compact dimensions allows it to fit just about anywhere, from a bedside table to a small patch of floor space. It's lightweight at 2.2kg, and can be moved between rooms easily, although for something this portable, the absence of a carry handle is a minor niggle.

Placed on the floor, the white cylindrical design is understated and functional, with a perforated lower section that draws in air and a circular grille on top that sends purified air back into the room. A touch-sensitive panel with controls for power, operating modes and display brightness, and a colour-coded air-quality indicator, round off the minimalist design. Just remember not to tuck it away behind furniture or in a tight corner; the purifier needs the air inlets and outlet unobstructed to draw air in and circulate the cleaned air out.

Having lived with Mijia products for years, I knew what to expect: a product that gets the basics right, with plenty of thoughtful little touches and smart flourishes thrown in for good measure. The Purifier 4 Compact doesn't disappoint on that front, and its smart features feel genuinely useful rather than like a checklist of things a connected appliance is expected to offer.

Through the Xiaomi Home app, you can control the purifier remotely, switch modes, set schedules and timers, and create automations. There's support for Amazon Alexa and Google Assistant for voice control, and a child lock prevents accidental changes to the settings. The app also lets users know when the filter needs replacing, taking some of the guesswork out of maintenance. And of course, while it can be operated using its onboard controls, the app is handy for finer control over fan speed. One drawback is that while air quality can be discerned via the green, yellow, orange and red colour-coded indicators, the lack of detailed numerical readings and historical trends is a missed opportunity.

The filtration system

The Purifier 4 Compact uses a three-stage filtration system -- a pre-filter for larger particles such as dust and hair, a HEPA filter for finer airborne particles, and an activated carbon layer for odours -- claiming to remove up to 99.97% of particles as small as 0.3 microns, including dust, smoke, pet dander and pollen. With a respectable-for-its-size particle Clean Air Delivery Rate (CADR), rated at 230 cubic metres per hour, the air purifier is most effective in smaller spaces such as bedrooms and study rooms, although Xiaomi says it can be used in rooms over 400 square feet as well. Larger rooms may benefit from a more powerful unit, while a smaller unit like this one will take longer to clean the air.

In practice, the purifier's biggest strength is its ability to work away in the background, and the 27W power rating makes it practical for extended use without resulting in a large electricity bill. Just leave it in Auto mode and its sensor adjusts the fan speed according to the detected air quality, spinning up when pollution levels rise and settling down once things improve.

One can hear it working harder when the air needs attention, but it's generally unobtrusive, particularly in a bedroom or home office. Sleep mode is even quieter, with a claimed noise level of just 20dB and the option to switch off the display. One caveat: the activated carbon filter takes a while to deal with strong cooking odours or incense.

Verdict

At ₹7,999, the Mijia Smart Air Purifier 4 Compact is an appealing entry point into air purification, or if you're looking for a second (or third) air purifier beyond the one in the living room. It's quiet, compact, easy to operate and sensibly equipped with smart controls. Its cleaning capacity is modest, the air-quality reporting basic and the odour removal nothing to write home about, but at this price, these feel more like reasonable compromises than dealbreakers.

Tushar Kanwar is a tech columnist and commentator, and tweets @2shar.