The QT3 is the latest addition to the Smart Air HEPA air purifier family, known for its small, compact, and lightweight design. This makes it an excellent choice as both a portable and desktop air purifier, ensuring clean air right at your desk or wherever you go.

But it’s not the first ‘portable’ air purifier on the market. So how does the QT3 portable air purifier compare with existing portable air purifiers? To find out, Smart Air compared four portable air purifiers on their cost, CADR (how much clean air it produces), noise levels, and size. When comparing prices, we used the prices from the Taobao e-commerce platform or the company’s official website.
Portable Air Purifier Comparison
1. Smart Air QT3 Portable Air Purifier. Price: $44.99

2. Xiaomi Mijia Desktop Air Purifier. Price: $59 USD

3. IQAir Atem Air Purifier. Price: $578 USD

4. Wynd Plus. Price: $199 USD

Cost vs. CADR
CADR is used to measure an air purifier’s effectiveness at cleaning the air. By comparing the cost and CADR of the portable air purifiers, we can see which is the most cost-effective or gets you the cleanest air for your dollar.

The QT3 portable air purifier had both the highest CADR and the lowest price out of all the purifiers compared. Its CADR of 37 m3/hr is 25% higher than the next best-performing purifier: the iQAir Atem purifier.
When looking at price, the QT3 is 1/6th the price of the next best CADR-performer and half the price of the next cheapest purifier (Xiaomi).
Comparing clean air delivered for every dollar you spend, the QT3 comes out at 3 times higher than the Xiaomi, and 24 times higher than the iQAir Atem.

Portable Air Purifiers: Noise & Size Comparison
Noise plays a crucial part in choosing an air purifier. This is especially true for portable air purifiers. Portable air purifiers typically sit close to the user, so a low-noise portable air purifier is crucial.

It turns out that the QT3 is the quietest with noise levels at 32 dB when running on ‘low’. On the other hand, the Xiaomi is nearly twice as loud at 60dB.
Moreover, the QT3 is the lightest amongst the purifiers at about 0.610kg.

It also occupies minimal space, with the second-lowest base area of 218 cm2, and a height of only 18cm.
Other Features of Portable Air Purifiers
It’s worth noting that the Wynd air purifier has a built-in and detachable air quality sensor. This can be useful for measuring the air quality away from the purifier and closer to the user, especially when outside the home. However, data shows that portable air purifiers like the Smart Air QT3 and the iQAir Atem work best when used within 60cm of the user. Knowing this, an air quality sensor may not be needed. In addition, our tests have shown some built-in air quality monitors to be quite inaccurate.
The Xiaomi air purifier also includes a carbon filter, for filtering out VOCs. This may be useful in newly renovated buildings, or when nearby smokers. However, its effectiveness has not been tested.
Finally, the Wynd and Smart Air QT3 portable air purifiers include batteries, which makes them great for use on the go. For example in taxis or Ubers, or in cafes where power is not available. The QT3 is powered using a USB-C port, meaning any portable power bank, laptop or phone charger can also be used to power it.

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I have two QT3s on my desk for a week now. While they might deliver the clean air as claimed here (i can’t measure), they are definetely not silent. In fact they are disturbingly loud, so that I can use them on level two at the most – if i opt for noise pollution over air pollution.
It seems the Squair gives 65 m3/hr at 6 Watts, better than the QT’s 40 m3/hr at 9 Watts. I’m surprised that the battery-powered item is less energy efficient; perhaps it’s the smaller size? (https://smartairfilters.com/en/product/sqair-air-purifier/, this article for QT figures)