Looks good, work really quiet on sleeping mode. To be honest I didn't feel very much changes, but I think after waking up it becomes more comfortable.

Purchased last December and placed in a study room with a smoker. It improved the air in the room by 80%. Also, on the low setting it is indeed silent and one can sleep comfortably. We will buy a second one as well. Of course, the price then was €140.

I was not satisfied at all...the machine is right next to the smoker and it doesn't pull anything, the smoke goes everywhere, wasted money

Wonderful purchase. Value for Money.
The indicators are easy and understandable. While the air is clean (the indicator shows 001), when we smoke it reaches 125 and it takes about half an hour to bring the environment back to 004.
No smell of smoke on my clothes when I leave the house.
It also quickly absorbs the smell of humidity in the small storage room.
I will buy it for my workplace as well.

Great product. i tookit becose my house is ground floor and had a terrible smell. now i dont have anymore that humididty smell.

does the job...sensitive sensor, noisy at full power and expensive filter.
With a wood stove and a smoker in the room it cleans just fine

Very good. We have allergies and as soon as I open the window, because we have pine trees outside the house, it immediately detects the pollen and responds. The most helpful thing is the automations you can set up.

it does what it promises regarding odors, it also collects dust but nothing crazy, after use when I took out the filter to blow it, you can't imagine what came out and obviously it has sucked up dust, it just doesn't collect all the dust

I have had the Mi 2H for many years
The 4 is awesome!

We have had it for almost a month now.
In a space where we smoke and use a stove, it reduces the particulates very quickly and has also worked well with dust; the filter has collected quite a lot. Just keep in mind that the square meters it claims are for when it operates at full power. For a 20-25 square meter space, it more than covers it. For our 70 square meter house, we will also get the pro version so they can cover better without needing to run at full power.
One last thing.
For better results, set up automations.
In auto mode, the speed drops very early at 120mg, so it takes a long time to reach 10-15mg and below, which is the safe level.
For example, I have set it so that when it reaches 40mg, it runs at speed 2, and if it goes to 80mg, it goes to full power, and as soon as it drops to ten, it switches back to auto mode.

The machine is good for odors and smoke, but since I got it for dust, it doesn't do much. After some time of use, if I shine a flashlight in the air, the dust is everywhere. I haven't noticed if there is less or no difference on my furniture.

I am satisfied both aesthetically and practically. It is also quiet in the respective settings.

Very good choice! It cleans the atmosphere in closed spaces from odors and dust. Finally, the house doesn't smell like cigarettes..

I researched it thoroughly before buying it and now, after months of use, I can say that it is one of the few devices that does exactly what it promises without needing constant attention. I have it connected to Home Assistant along with a bunch of other sensors like air quality, humidity, and even motion sensors in the house, and everything works perfectly—no disconnections, no settings lost, it just works. You can set up automations on it without worrying, and honestly, after a while you forget it's running because the results are consistent... The dust has almost disappeared; I used to have to dust every few days, especially shelves and electronics, and now I only do it out of habit and there’s nothing there... It’s silent, it doesn’t have flashy lights or make noise, it just exists and works in the background, and for me, that’s its best feature.

It is used in a small room so it is a bit overkill. However, it does its job perfectly and is silent.

I bought it 10 days ago, it cleans the atmosphere well, but the light indicator broke, it lights up for a while and then the display with the indicators turns off

I have bought a Purifier 4 and a 4 Lite. One for the office and one for the living room. I mostly bought them because I had the impression that they remove odors from the space, such as cooking smells when you fry, for example. In my opinion, this is not the case. However, it does a very good job with smoke and cigarette odor. The only thing I would say I don't like about the device is that the sensor is very sensitive. That is, with a lit cigarette, it suddenly goes from 005 (good air quality) to 300, and after a few seconds to 120, etc. As a result, the fan speed goes up and down at the same time, which is a bit annoying since it makes quite a bit of noise when it's at the highest speed. This is always in auto mode. Other than that, I am very satisfied with the performance-to-price ratio.

Generally useful device, the only problem is that the cable doesn't fit well, resulting in it coming out very easily

It was installed on the ground floor of a single-family home due to the systematic use of a (closed) fireplace. The particles on the day it was installed were over 30 and since then it has consistently kept them below 5-6. If we open windows, I notice that it often rises above 20 (neighborhood with many fireplaces/stoves), so its use is more effective than just opening to ventilate. It does a very good job with kitchen odors as well. The noise is very tolerable; it is only heard when we set it to a high level in manual mode for a few minutes to quickly clean the atmosphere (e.g., when we suddenly open the fireplace door and there happens to be smoke). In automatic mode, it is completely silent.

Humidity and temperature meters that seem to be accurate with some comparisons I made with other devices and a mercury thermometer. Easy connection to the modem. Personally, I unplug it to move it to other areas, and as soon as I plug it back in, it connects to the modem again in a fraction of a second so you can control it from the app. You can set it to operate on 3 different intensity levels or select the square footage of the area it needs to cover, and it works on its own at a constant intensity, or you can set it to automatic, which adjusts the fan's operation based on the room's pollution. At the lowest intensity, the fan makes it "silent."

Classic XIAOMI device for air cleaning use in a home from cigarette smoke, dust, and exhaust gases. The question is how many years it will remain silent and whether we will find replacement filters.

Incredible product, does exactly what it describes, makes a little noise, cleans the cigarette and odors in general, you really feel a clean atmosphere!

Very good machine and very high quality construction. In normal operation (auto), you can't hear anything at all. The fan will increase its speed when it detects a large amount of particles. In a few hours, the PM2.5 levels reached zero, confirmed by the awair monitor that is in the same room, which provides very accurate measurements.

It works correctly with home assistant and provides sensors for air flow, filter life remaining, particles, etc.

Finally, something that many forget, the price of the filters! In this machine, the 3-stage filter costs about 30€ and lasts 6 to 12 months depending on the pollution of the space. In other machines (e.g. winix), the price is more than double.

I have placed it in a smoking area and I can say that it makes a big difference. Of course, it needs to work at its maximum and it makes a little noise, but not to the extent that it is annoying. The filter will need to be changed around 1 year, so it's worth it.