A Smart & Efficient Air Purifier Review: The Xiaomi Mi 3H

Full Review

The Xiaomi Mi 3H air purifier is from a well-known and proven Chinese brand. It’s the successor to the popular Xiaomi 2 series air purifiers.

This new generation of Xiaomi air purifiers brings many new features and improved technology while keeping the same filtration technology as its predecessor. They even use the same size filters.

However, the most significant improvements over the previous models are the higher CADR, better quality fan, and increased airflow.

This is an ideal air purifier for living rooms, large bedrooms, offices, and almost any other place. The Xiaomi Mi 3H is one of the best value-for-money air purifiers we tested.

How We Tested the Xiaomi Mi 3H?

1. For the filter efficiency testing, we used the Temtop LKC-1000S laser particle meter, which measures PM2.5 (µg/m3), PM10 (µg/m3), Particles (per/L), and HCHO (mg/m3) in the air, and also calculates the AQI.

2. We placed the Xiaomi Mi 3H in two separate performance tests, one in a 320 sq. ft. (30 m²) room and the other in a 560 sq. ft. (52 m²) room. Then, we recorded the initial air quality values using the Temtop laser particle meter and let the Xiaomi Mi 3H run at maximum speed.

3. After 60 minutes, we measured the new values using the Temtop laser particle meter and saved the data.

4. Next, we placed the Xiaomi Mi 3H in a glass box, which we then filled with smoke. Then, we measured how much time was needed for the air purifier to remove all the smoke from the box.

5. Using a special noise measurement tool, we tested the air purifier’s noise level at all speeds. We measured the noise level on the dBA scale.

6. Finally, we measured the power usage at all speeds using an energy meter, after which we calculated how much it would cost to use the device at a particular fan speed for one month. For reference, we used an energy price of $0.12 per kWh.

The Xiaomi Mi 3H is a large device with a CADR of 223 CFM (380 m³/h), making it ideal for large rooms.

I would recommend using it in rooms up to 484 sq. ft. (45 m²), where it will clean the air 4.8 times in one hour.

Besides the standard testing procedure we do with every air purifier, I have used the Xiaomi Mi 3H for some time, and all I can say is that it’s the kind of device I would continue to use in my home: it’s efficient, smart, and affordable.

Testing in a 320 sq. ft. (30 m²) Room

In the first test in a 320 sq. ft. (30 m²) room, the Xiaomi Mi 3H made outstanding results.

It worked at maximum speed for 60 minutes and reduced the PM2.5 particulate matter from 96.5 to 5.1 µg/m³. This was an air quality improvement of 95%, which is a fantastic result, even though the room was a bit smaller than the recommended dimensions.

Such great results put the Xiaomi Mi 3H in the range of, and even above, some top-class air purifiers.

I won’t say anything more but suggest checking the chart above, where I listed the testing results of some of the most popular Xiaomi competitors.

Testing in a 560 sq. ft. (52 m²) Room

In the second test, in a room of 560 sq. ft. (52 m²), the Xiaomi Mi 3H worked for 60 minutes at the highest speed, and during that time, it improved the air quality by about 90%.

Considering that this room is larger than the recommended dimensions, this is also a great result. It reduced the PM2.5 particulate matter from 83.7 to 8.2 µg/m³.

With this test, we once again confirmed that the Xiaomi Mi 3H is a competitive and highly efficient air purifier.

Performance – Smoke Removal Test

In the smoke removal test, the Xiaomi Mi 3H did a pretty good job. It took only 15 seconds to remove all the smoke from the glass box.

This is one of the fastest results among all the air purifiers we tested.

As you can see in the chart above, only the Blueair 211+ was faster in this test; it removed all the smoke in just 9 seconds.

I really like that the Xiaomi Mi 3H uses five different fan speeds, including the sleep mode, which is one of the quietest among all tested devices so far.

In sleep mode, the Xiaomi Mi 3H produces a sound level of 40.9 dBA. If we compare this result with some other competing devices at the lowest speed, we can easily conclude that Xiaomi is one of the quietest.

If you look at the chart, you will see that only the Winix 5500-2 is quieter, producing a sound level of just 40.6 dBA.

However, at the maximum speed, the Xiaomi Mi 3H is one of the loudest air purifiers tested. It produces a sound of 65.4 dBA at this speed, but I wouldn’t consider this a problem, mostly because you won’t use it at max speed very often.

Below is a table showing the noise at all speeds.

All in all, the Mi 3H is a very quiet air purifier and a device that won’t interrupt your daily activities or your sleep if you decide to use it in the bedroom.

The Xiaomi Mi 3H is a low-power consumer. It uses a motor of only 38W, meaning it’s extremely well-optimized and has an excellent power-to-CADR ratio.

If you were to leave the Xiaomi Mi 3H running 24 hours a day for a month at maximum speed, your electricity bill would increase by about $3.42, which is reasonable and not too expensive.

Moreover, the Xiaomi Mi 3H will cost you much less than some other competing devices. The Coway AP-1512HH, under identical conditions, will cost you about $6.05, which is significantly higher, especially considering that Coway has a much lower CADR compared to Xiaomi.

However, in addition to the electricity cost, there is also the cost of replacement filters, which is slightly higher. Fortunately, the filters on this device need to be replaced on average every 6 to 12 months.

All in all, if we sum up the electricity consumption and the price of replacement filters and take into account the high CADR and what you get with the Xiaomi Mi 3H, we can conclude that this isn’t a huge consumer and is generally affordable to maintain.

Filtration Technology

The Xiaomi Mi 3H uses a 3-in-1 True HEPA filter, which comes with the device. 3H uses an Integrated 360 ° cylindrical HEPA filter.

In addition to the default filter that comes with the device, it is possible to purchase Anti-formaldehyde S1 and an Antibacterial filter. All the tests I did were on the default filter; I didn’t have a chance to test the other available filters. If I get my hands on them in the future, I will update the review.

Xiaomi Mi 3H uses a true HEPA Class 13 filter, a big step up from the previous model. What is important to note is that this filter is also compatible with older versions of the Xiaomi air purifier.

The first stage of filtration is the pre-filter, whose primary purpose is to remove hair, dust, cotton fibers, and other large particles.

The second stage of filtration is the True HEPA filter, which is credited with effectively eliminating cigarette smoke, PM2.5 particles, pollen, dust, pet dander, and other allergens as small as 0.3 microns from the air.

The third and final stage of filtration is the active carbon filter. This filter adsorbs formaldehyde, volatile organic compounds (VOCs), and other harmful gases. The carbon filter is filled with carbon pellets, but this is a fibrous filter coated with carbon. What I like besides the quality of filtration is the size of the filter, easy replacement, and easy maintenance.

How to Replace the Xiaomi 3H Filter?

The Xiaomi Mi 3H uses a filter indicator to notify you when it is time to replace the filter. This period is on average between 6-12 months, approximately 150 working days. You will receive an alert on the application as well as on display located on the device. The current status of the filter is shown on display each time the device is switched on.

The filter replacement period will often be over 6 months; it all depends on how well you maintain the filter and how often you use the device. However, my recommendation is to check the filter periodically if it is too worn out. You may need to replace it earlier.

In addition, periodically clean the air intake vents on the outside with a cloth, and be sure to vacuum the air intake vents on the inside at least once a month. These actions extend the filter life and protect other filters, as well as improve device performance.

Always use the genuine Xiaomi filter; otherwise, the device may not recognize and accept the filter.

Total time: 10 minutes.

Setup and Installation

Xiaomi Mi 3H does not require complicated preparation before the first start of the device. The filter is entirely ready to use, located in the machine. However, before starting, it is necessary to open the cover on the back of the device and remove the power cord, which is located there. You can then connect the power cord to the device immediately. The input is located just below the cover on the back. I don’t like that the power cord is very short, and in some situations, I wish it was longer.

Before placing the device in the desired location, keep in mind that it is necessary to move it away from the wall at least 20 inches (about 50cm) on all sides.

Design

The Xiaomi 3H air purifier is a minimal device, white in color except for the gray grilles on top and black display. The quality of manufacture is at the highest level, the plastic is very high quality, and everything is in place.

One of the most significant drawbacks I would mention when it comes to design is that the 3H does not have a carrying handle, so the device is tough to transfer from room to room. While this is a larger device designed for larger rooms that you may not carry so often, I still think this option on the machine wouldn’t hurt.

As for the general feeling, the device is lovely and modern. It easily fits into almost any environment. Another drawback I could add to the design is the very short power cord, which very often limits the ability to place the air purifier in the desired location.

OLED Display for Device Control

The OLED display is an improvement over the previous series (Xiaomi 2) air purifier. The screen is very readable, practical, and just what it should be for this type of device. The display is located on the front of the device.

Sometimes it’s a little harder to use the display due to the awkward position. Still, personally, it’s not a problem for me because I’ve almost always used 3H via a smart app. I recently tested the Afloia Mage, which uses a display in an identical position. However, I have to commend Xiaomi as this display is much more practical, readable, and of better quality.

Only one button on display serves for complete control of the device and indicators. The control button can be used to change the mode, connect to Wi-Fi, or turn the device on or off. The indicators shown on display are PM2.5, temperature, humidity, Wi-Fi, and mode indicators.

Airflow

Although the Mi 3H uses a circular filter, the device is not open on all sides. Mi 3X draws air through the holes, which occupy the lower half of the device. The holes are arranged on three sides, on all sides except the back (filter cover). The air is then filtered and exits through a grille at the top of the device.

Size and dimensions

The air purifier weighs 10.6 lb (4.8 kg). The dimensions of the device are: 9.5 x 9.5 x 20.5 inches (24 x 24 x 52 cm).

What’s in the box?

When you buy the device, you get a 1x Xiaomi Mi 3H air purifier, 1x power cord, 1x True HEPA filter, and 1x user manual. Xiaomi is a bit specifically packaged, as I already explained at the beginning of the review, so don’t be confused by the fact that the power cord is located inside the device, in the space where the filter stands. If you still have problems with unpacking, I suggest you go back a bit and read the detailed explanation.

Features Overview

The Xiaomi 3H is packed with a variety of advanced options that can be controlled directly on the display or through a smart app. I recommend connecting the device to the app to access all the features. Below, I will explain some of the most important options you can find on the Mi 3H air purifier.

Smart APP (Mi Home)

The Xiaomi 3H has no reason to be the epithet of the smartest air purifier I’ve had the opportunity to test so far. In addition to the classic device control, there is also the Mi Home application, which is available for Android and iOS devices.

The application is handy, full of advanced options, and very easy to use. I will write more details below to touch on some peculiar options that just caught my eye.

Air Quality Sensor and Indicator

The Xiaomi Mi 3H has several different sensors. However, the primary and most important of all is the Air Quality Sensor. This sensor is located on the back of the device. This is essentially a laser particle sensor that detects the amount of dust in the air in real-time. It also can detect smoke and some VOCs.

Real-time air quality is shown on display and on the smart application. The display shows PM2.5 particles. In addition, around the “turn on” button is an indicator that will light different colors depending on air quality.

If the amount of PM2.5 is between 0-75, the air quality is good, and the indicator around the power button will light green. If the amount of PM2.5 is 76-150, the air is moderate, and the indicator will glow orange. If the amount of PM2.5 particles is over 150, the indicator will light up red.

If you connect a smart app to the device, you will see the current Air Quality Index.

It is essential to know that the Air Quality Sensor has a unique small motor that works separately from the air purifier. As soon as you plug in the Mi 3H, the Air Quality Sensor will start measuring the air quality (the small motor will start working). It is possible to read the current air quality on the application at any time. This is very useful if you want to set the device to turn on if the amount of PM2.5. exceeds a specific level.

Temperature and Humidity Meter

Temperature and humidity sensors are located just above the particle sensor, on the back of the device. This is a perfect addition because you will have a complete picture of the air quality in your room.

On the application and on display on the device, you can see the temperature and humidity in real-time. I like that the Mi 3H abounds with a multitude of sensors for a variety of purposes.

Auto Mode

Auto mode is a handy option, mainly because of the quality, sensitivity, and exact smart sensor. I say that because auto mode works in combination with a smart sensor. When auto mode is on, the Mi 3H will shift the fan speed depending on the current room air quality.

Manual Mode

This is an innovative option that I have only seen so far with the Smartmi P1 air purifier. Namely, manual mode is a manual speed adjustment, with the help of a slider integrated into the application.

What I like is that this mode allows the freedom to choose the speed in a way that you have the option to select the speed of the motor in addition to the offered speeds. Manual mode works by adjusting the room coverage, and in this way, the device itself adjusts the fan speed.

This is a perfect option if you plan to use the device in smaller rooms, so this way, you can customize it for the dimensions of that room. To set the manual mode, you need to connect the air purifier to the smart app. When manual mode is active, on display, a heart-shaped indicator will appear.

Parental Controls

Suppose you want to protect the device from accidental button push and change of settings. In that case, this option is ideal for you.

Also, if you have small children, this is ideal for preventing any action by pressing a button on the device.

Parental controls, when active, disables all actions by clicking the control button located within the display on the front of the device. It is important to note that this mode can only be activated via a smart app.

Sleep Mode

This is a perfect option, especially if you plan to use the Mi 3H in a bedroom or similar room. When in sleep mode, the device produces ultra-low noise for a comfortable sleeping environment.

However, when in sleep mode, the display will not turn off. If you want to turn off the display, you can do so via the smart app or by pressing the display off button located on the back of the device.

Display Off Button

Since the Mi 3H does not dim the display when in sleep mode, this is an excellent option to dim or turn off the display completely.

You can do this in two ways. The first is by pressing the button on the back of the device, just above the Smart Sensor. The second way is with the help of a smart application.

Scheduled Power On/Off

The Mi 3H uses an advanced timer that can be set in many different ways.

The timer is so advanced and is very different from similar options on some other devices.

Through the application, you can set the time when you want the device to turn on, the time when you want it to turn off, or even the period when you want the machine to work. I think this is quite enough for every user to program an air purifier in a way that suits them best.

Google Assistant and Amazon Alexa Integration

Since the Xiaomi air purifier can be controlled with the help of the Xiaomi Mi Home App, it is straightforward to connect it to Google Home or Alexa.

All you need to do is add the Mi-Home app to Google Home, and you’re ready to launch Mi 3H by voice. Depending on what you prefer, you can opt for Google Home or the Alexa voice control device.

Certified and Ozone Free

Mi 3H is a certified device according to recognized standards. Xiaomi 3H does not produce ozone and is entirely safe to use. CARB is certified, which is a confirmation of this fact.

Smart APP (Mi Home)

The Xiaomi Mi Home app is available for Android and iOS platforms.

It is a universal application with which it is possible to connect all Xiaomi devices and create a Smart Home environment.

Although the application is not strictly created for the Xiaomi Mi 3H, it is full of advanced options and controls that significantly facilitate using the 3H air purifier. Of course, there are some disadvantages, which are present precisely because the app is universal. One of the most significant deficiencies is the option to show a chart of the air quality over the last 30 days. I used this option with the smart app for the Airdog X3. It is beneficial, and I liked it a lot, so I would like Xiaomi to offer something similar.

Below I will explain some of the most important options that the application offers. You can find the application on the Android or iOS store, download and install it. An important note is that the application requires registration with a valid email address.

Add Device and Home Screen

To add a device, you must open an account. Register on the app. I did it in one step because Mi Home allows you to register via Facebook.

Before we start connecting the Mi 3H to a smart device, you need to turn on the air purifier and turn on the Bluetooth on the smartphone. The next step is to click on the “+” located in the upper right corner. Then, on the screen, you will notice that the smart app searches for available devices. When the Mi Air Purifier appears in your list, click on it.

The next step is to choose a Wi-Fi network to connect the Mi Home app with the air purifier. After selecting the network, accept the terms and click “Next.”

After successfully connecting the device, you need to choose some aesthetic settings to find your way around the application more efficiently.

First, a screen will appear to select the room in which the device is located. The second step is adding the product name. I will leave the default name because I currently use only one Mi 3H air purifier, so it is impossible to get confused. The last step is to share the device with other household members who have access to the application.

Control options

The home screen offers a variety of options. The first options you will see after turning on the device are: PM2.5 indicator; just below it is the readings of temperature and humidity. Below is a button to turn the device on or off, and under are buttons to control the operation of the device.

The buttons for controlling the operation of the device are auto mode, sleep mode, fan speed ​​, and manual mode. If you scroll down, you will see many more different options and information. 

Right at the beginning is the filter status that displays the current filter wear and displays the time it will take to change it. Below the filter display are various options; option titles tell you what they are about and their purpose. I’ll leave those options to you to play with, and for all the uncertainties, don’t hesitate to ask a question in the comments.

Automation

The Mi Home application has one handy option: Automation, which in translation means setting the conditions based on which the device will do certain things.

Xiaomi allows you to set various conditions. So you can set the Mi 3H to shut down if the amount of PM2.5 particles is below a certain number. Or to start itself if the amount of particles is above some number.

You can also turn the device on or off, depending on the temperature and humidity in the room. Basically, this is a lot of options. I think that each user will need some time to get used to all that options, try everything, determine what he needs most and what he could use daily.

Room Coverage and CADR

Xiaomi Mi Air Purifier 3H is designed for rooms up to 484 sq. M. ft. (45 m2). This device is ideal for a large room such as a living room, a large bedroom, or any room of larger dimensions.

However, it will also work very well in smaller rooms, especially with manual mode, which will make it easier for you to set up the device for smaller rooms. Xiaomi uses the new powerful air duct system that delivers 6330 liters of purified air per minute in this model.

The CADR for the Mi 3H model is 380 m³/h. The company developed a rear-tilting centrifugal fan that can move air more effectively. They also made a new direct-current brushless motor. The newly created pressurized air duct and the air grille form an even more effective airflow path, considerably boosting the purifier’s performance.

FAQ on Xiaomi Mi 3H