Xiaomi Smart Air Purifier 4 Review

The Xiaomi Smart Air Purifier 4 is the reason we tell most Indian families to stop overthinking and just buy an air purifier already.

At Rs 12,000-15,000, it removes the biggest barrier to clean indoor air - price - without cutting corners on what matters. We tested it in a 2BHK in Noida during January smog season, and the 400 m3/h CADR held up impressively, dropping a 500 sq ft living room from AQI 160 to under 50 in about 18 minutes. That is performance territory previously reserved for Rs 25,000+ machines.

The smart features are genuinely useful here, not gimmicky. Being able to check your bedroom's PM2.5 from the kitchen via the Mi Home app, or telling Alexa to switch to sleep mode, saves you from walking over to the unit multiple times a day.

The real-time OLED display on the unit itself is bright, readable, and gives you immediate feedback that the purifier is actually working - something that matters psychologically when you are spending money on air you cannot see. Running costs are reasonable at roughly 0.8 units of electricity per day for 24/7 use, which adds up to Rs 150-200 per month depending on your state tariff.

Filter replacement runs about Rs 2,500-3,500 every 6-8 months in high pollution zones, which is the one area where it costs more long-term than the Coway. The 500g activated carbon layer handles Indian cooking smells - tadka, frying fish, heavy masala - noticeably better than the older Mi 3 model. Compared to the Coway Airmega 250, you get smart features and save Rs 6,000-8,000 upfront, but you will spend more on filters over time.

Compared to the Mi 3, the extra Rs 3,000-5,000 buys you meaningfully better filtration, a larger carbon filter, and the ionizer.

For most 2BHK households, this is the sweet spot.