Expert rating
Advantages
- Lots of data available on its control panel and in the Smartmi app
- H13 HEPA filter and activated carbon filter, plus UV-C sterilizer
- Apple HomeKit compatibility
The inconvenients
- Inexcusable problems with firmware updates
- Extremely noisy at high speeds
- Very low smoke CADR
Our opinion
Nearly insurmountable issues with firmware updates hamper this otherwise solid air purifier.
Price when reviewing
$259.99
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$259.99
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Smartmi Technology
$259.99
Of all the smart home products that come through my doors, you wouldn’t think that a simple air purifier is one of the most troublesome devices I’ve tested in years. And yet, here we are, with the Smartmi Air Purifier 2, a product that I almost threw out the window in frustration for a good two weeks of testing.
But before we get to that, let’s cover some basics. The Smartmi 2 is a cylindrical tower style purifier, 22 inches high and 11 inches in diameter. At 12 pounds, it’s easily maneuverable to be placed just about anywhere, with 360 degrees of air intake through the base, pushed through the cylindrical H13 HEPA filter and emitted upwards from the top of the device. A set of touch controls are available in the center of the exhaust grille, but there are only two pressable buttons, a power button and a mode cycle button that guides you through auto, sleep and favorite (you can set this last one in the app of Smartmi).
This review is part of TechHive’s coverage of the best smart air purifiers, where you’ll find reviews of the competition’s offerings, plus a buyer’s guide to features to consider when buying of this type of product.
A host of additional indicators are available on this surface, including a color-coded “pollen alert” indicator (which measures PM2.5 and PM10 pollution), a separate digital PM2.5 indicator, a temperature readout, a bar graph indicator of total VOCs (compounds volatile organics), and finally a colored ring surrounding it all which is calculated based on PM2.5 and VOC levels. That’s a lot of data to play with, and it’s even more than what you’ll get through the app.

The touch surface on the top of the Smartmi Air Purifier 2 displays lots of useful information about your indoor air quality.
Christopher Null/Foundry
Claimed CADRs (clean air delivery rates) are 223 cubic feet/minute for dust, 206 for pollen, and (oddly) only 60 for smoke. The maximum effective room size is 484 healthy square feet, with air being replaced three times per hour. Filters ($50) have a lifespan of 6-12 months, depending on usage.
The Smartmi Link app has many more features than the built-in control panel. If you want to manually adjust the fan speed, that can only be done through the app using a slider rather than preset levels, although things get terribly loud (64dB max) beyond half of the speedometer. An internal UV-C light can be turned on – again, only in the app – if you want to zap germs with ultraviolet light, and features like a scheduler and delayed shut-off can also be accessed in the application. The app can turn off the Smartmi 2 beeps and offers child lock and temperature and humidity readings.
You’ll need to connect the Smartmi to your 2.4GHz Wi-Fi network to do any of these things, and that’s where the fun really started for me. As the device connected to my wireless network within seconds, I was greeted in the app with a strange notification that my filter – just taken out of the plastic – was at the end of its life, the temperature was – 4 degrees Fahrenheit and a firmware update was needed. I thought the first two issues were due to the third one, so I dutifully followed the instructions to install said update. The process was slow, until about 30% complete until, like that, it stopped, prompting me to “try again”.

Our reviewer encountered a host of issues with the Smartmi Air Purifier 2, starting with its app notifying that its filter should be replaced as soon as it turned it on. Firmware updates fixed most issues, but installing them was a huge hassle on its own.
Christopher Null/Foundry
And I did, multiple times, for almost two weeks, sometimes reaching 85% completion, sometimes getting stuck at zero for 10 minutes, but invariably ending with “trying again”. I tried everything from unplugging and powering the device back on, force closing the app, disconnecting and reconnecting, but nothing worked. Eventually, I was connected with a Chinese tech support team — six people in total — on a Zoom call to resolve the issues. The first piece of advice I was given: “Follow the manual.”
The support call was particularly unhelpful, with the specious consensus being that the update was taking too long because my network connection was too slow, and maybe I should try connecting to a different Wi-Fi network. , like my smartphone hotspot. This didn’t work because the app couldn’t see my cell phone’s hotspot – or handle a manually added Wi-Fi network with a space in it – which ultimately sent me back to the drawing board . What finally worked—on day 11– was simply brute-forcing updates. I just tried again and again until after a few 98% completions one finally succeeded.
That way I was able to get the actual temperature, not be alerted to new but used filters, and even connect the Smartmi 2 to Apple’s HomeKit ecosystem, which is a nice feature to have, if not entirely useful account held it only has some of the functionality of the app itself. Alexa and Google Assistant are also supported if you want voice control on the device.
Of course, you’ll have to get those firmware updates working if you want to do all of that – Homekit was DOA until day 11 for me – and that could be a big plus if your experience is close to mine. Is it really likely that my internet data plan can’t handle the intense bandwidth demands of the Smartmi 2 firmware download? While anything is possible, I suspect that these devices really need to update their firmware before leaving the factory.