Why Xiaomi Air Purifier is Buzzing: Causes and Ways to Eliminate

Xiaomi air purifiers have long proven themselves to be reliable assistants in the fight against dust, allergens and unpleasant smells. But even the highest quality devices sometimes begin to make unusual sounds, from a quiet buzz to a loud hum. If your Xiaomi air purifier suddenly becomes more noise than usual, this is not always a cause for panic: in 80% of cases, the problem can be fixed on its own.

In this article, we will discuss 7 The main causes of hum in Mi Air Purifier models 2/3/4, Smart Air Purifier Pro and others, and step-by-step diagnostic instructions, you will know when noise is the norm (e.g., at the top speed of a fan) and when it signals a critical engine or bearing malfunction requiring professional repair.

We will focus on common user errors that lead to increased noise: incorrect installation of filters, ignoring signals to replace consumables or operating in high humidity conditions. We will also provide data from Xiaomi laboratory tests, which show how noise level depends on the degree of pollution of filters and mode of operation.

1.Contaminated HEPA-filter is the main cause of the hum

According to statistics from service centers, 65% of complaints about the noise of Xiaomi air purifiers are related to clogged filters. HEPA H13 Or the carbon filter is filled with dust and microparticles, the air has to overcome more resistance, and the fan runs at the power limit, which causes the hum.

How it manifests itself:

• 🔊 Noise increases gradually, over 1-3 months
• 📉 Reduced cleaning efficiency (the device reaches the target level longer) PM2.5)
• 🔄 The device often switches to high speed
• 🚨 On the screen, the filter replacement indicator is lit (in models with a display)

In the Mi Air Purifier models 3H And the newer system itself alerts you to critical filter contamination through the Mi Home app, but even if you don't have an indicator, check the filter visually, if it's gray or black, it's time to replace it. Ignoring this problem leads not only to noise, but also to overheating of the engine and reducing the service life of the device by 30-40%.

⚠️ Attention: Do not try to wash. HEPA-It destroys the fibrous structure of the filter and renders it useless.

Incorrect installation of filters

Even a new filter can cause a hum if it is installed incorrectly. In Xiaomi models, filters are fixed with magnets or latches, and the slightest distortion leads to vibrations, especially after replacing the consumables, when users do not fully fix the filter or put it upside down.

Signs of improper installation:

• 🔧 The hum appears immediately after the filter is replaced.
• 🌀 Vibration is felt when you put your hand to the body
• 🔍 There is a gap between the filter and the body

How to check:

1. Turn the cleaner off the socket.
2. Remove the front cover (in most models it is attached to the latches).
3. Make sure the filter is flat, without skewing, and all magnets (if any) match the metal plates on the case.
4. Close the lid before you click – the Mi Air Purifier 4 Pro should sound the characteristic fixation sound.

In the cleaners Xiaomi Smart Air Purifier FJY4012GL And the likes of a circular filter, if you look at the directional arrows on the filter body and the device, they should match. If you put the filter in front of the airflow, it not only increases noise, it also reduces cleaning efficiency by 20 to 25 times%.

Wear of fan bearings

If the hum is accompanied by metal grinding or periodic clicks, the problem is most likely in the bearings of the engine. Xiaomi cleaners use fans with ball bearings, which over time wear out due to:

• 🕒 Long-term operation at maximum speed (more than 5000 hours)
• 🌡️ Overheating due to clogged filters
• 💧 Moisture infestations (if the device worked in the bathroom or kitchen without hooding)

Diagnosis:

Mi Air Purifier Pro and Mi Air Purifier 3C Fan bearings are maintenance-free - they can not be lubricated without disassembling the body. If you do not have experience in repairing equipment, it is better to contact the service center. The average cost of replacing a bearing unit in official Xiaomi services is from 1500 to 2500 rubles.

⚠️ Warning: Dust from worn bearings can get into the air and reduce cleaning quality.If you notice metal dust inside the case, immediately stop using the device before repair.

4. Intrusion of foreign objects

One of the most obvious but often overlooked causes of hum is foreign objects inside the purifier.

• 🧶 Foil, hair or pet hair (especially for cat and dog owners)
• 🍃 Leaves, plant seeds or poplar down
• 🧸 Small details of toys (if the device is in the children's room)
• 📄 Scraps of paper or polyethylene

How it happens is that foreign objects are sucked through the air holes and wound onto the fan axis, and over time they form a dense lump that interferes with the rotation of the blades and causes vibration, and in some cases, this can lead to a jamming of the engine.

What to do:

1. Disconnect the cleaner from the network.
2. Remove the front cover and filters.
3. Carefully examine the fan blades (in Xiaomi models they are usually white or gray).
4. If you find wound hair or threads, carefully remove them with tweezers or a wooden stick.
5. Blow the body with a vacuum cleaner at minimum power.

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To prevent wool from getting in, use a prefilter made of nonwoven material (sold separately) that traps large particles and prolongs the life of the main material. HEPA-filter.

In the cleaners Xiaomi Mi Air Purifier 2S And like the vertical fan, foreign objects often accumulate in the bottom of the body. To remove them, flip the device (after removing the filters) and shake. Be careful not to drop the cleaner, because this can damage the sensors. PM2.5.

5. Maximum speed operation

Many users confuse normal noise at high speeds with a malfunction, and in Xiaomi models, the noise level depends on the chosen mode:

• 🌬️ Sleep mode: 22-28 dB (almost silent)
• 🔄 Automatic mode (Auto): 30-45 dB (depends on air pollution)
• 🚀 Maximum speed (Turbo): 50–60 dB (comparable to air conditioning)

If your cleaner only buzzes when Turbo mode is turned on or when the sensor detects a high level PM2.5 (For example, during cooking or cleaning, it is not a breakdown, but normal operation of the device. In the instructions for the Mi Air Purifier 4 and Smart Air Purifier Pro, it is indicated that at maximum speed noise levels can reach 62 dB, which is comparable to loud conversation.

How to reduce noise:

• 📱 Use Automotive Mode (Auto) – the device will adjust the speed of the fan itself.
• 🕒 Turn on Turbo only when urgently needed (for example, after repairs or if someone smoked in the room).
• 🏠 Install the cleaner away from the bed – noise of 50 dB at a distance of 2 meters is perceived as 35-40 dB.

In models with Display-off function (for example, Mi Air Purifier) 3H) You can turn off the backlight of the display at night - this will not reduce the noise, but will make it less noticeable in the dark.

6. Engine or electronics malfunction

If all previous causes are ruled out, but the hum remains, the problem may be in the electronics or the engine, the most serious malfunctions that usually require professional repair.

Engine malfunction:

• 🔥 The hum is accompanied by the smell of burning or melted plastic
• 🛑 The fan spins in jerks or stops
• ⚡ The device shuts down after 5-10 minutes of operation (heat protection is triggered)

B. Problems with management fees:

• 🤖 The hum appears only in certain modes (for example, in Auto, but not in manual mode)
• 📵 The cleaner does not respond to buttons or commands from the app
• 🔄 Modes switch randomly

In Xiaomi Mi Air Purifier Pro H and similar inverter engines, the failure is often associated with the failure of the power transistor on the board. It costs 2000-3,000 rubles to replace it. If the engine itself burns, repairs may not be cost-effective, in which case it is easier to buy a new cleaner.

⚠️ Warning: If you smell a burn, immediately disconnect the device from the network and do not turn it on until the diagnosis!

For primary diagnosis, you can use the test through the Mi Home app:

1. Open the app and select your cleaner.
2. Go to Settings. → Diagnosis (in some models, this item is called Self-checking).
3. Run a fan test. If the engine is faulty, the app will show an error (e.g., Error 2 or Motor fault).

External factors: humidity, temperature, vibration

Sometimes the hum of Xiaomi air purifier is caused not by internal malfunctions, but by external conditions.

A. High humidity:

• 💦 If the cleaner is working in the bathroom or kitchen during cooking, moisture can condense on the fan blades, causing an imbalance.
• 🍄 In damp rooms, mold may appear on filters, which increases air resistance.

B. Uneven surface:

• 🪨 If the cleaner is on a soft carpet or sloping surface, the vibration from the fan is enhanced.
• 🔧 In models with a round base (for example, Mi Air Purifier 3), even a slight skew leads to a "beat" of the body.

Temperature differences:

• ❄️ When working in a cold room (below) +10°C) the plastic of the shell may be slightly deformed, causing additional noise.
• 🔥 In hot conditions (above) +35°C) the engine is operated with increased load, which increases the noise level.

Decisions:

• 🌡️ Install a cleaner in a room with a temperature of 15-30°C and humidity 30-60%.
• 🏗️ Place the device on a flat, hard surface (for example, on a table or stand).
• 🚫 Do not place a cleaner near heat sources (batteries, heaters) or cold (air conditioners).

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The optimal place for an air purifier is at a distance of 30-50 cm from the walls, away from direct sunlight and moisture sources.

In Xiaomi Smart Air Purifier 4 Compact and similar models with small dimensions, it is especially important to monitor the ventilation gaps. If the device is close to the wall or furniture, air circulation is disturbed, and the fan operates with increased load.

FAQ: Frequent questions about the hum in Xiaomi cleaners