Comparison Xiaomi Smart Air Purifier 4 vs Xiaomi Mi Air Purifier 3C

A very conditional parameter that slightly characterizes the purpose by the size of the room. And depending on the height of the ceilings, layout, structure of the building and equipment, the actual values ​​​​may differ significantly. Nevertheless, this item represents the maximum recommended area of ​​​​the room in which the device is able to effectively clean the air. The parameter is indicated taking into account the standard ceiling height of 2.5-3 m. If the ceilings are higher than generally accepted values, the volume of space increases — it can be recalculated using special formulas. If the unit is used in rooms larger than the specifications of the model, the air cleaning quality may be poor, and maintenance and filter replacement may need to be done too often.

If the device is supposed to be moved from one room to another, when choosing, you should focus on the room with the largest area. In any case, it is recommended to take equipment with a reserve for the serviced area, but a small one – otherwise the device will cost more and may turn out to be more bulky.

— Hygrostat. A feature that allows you to maintain a constant level of humidity in the room. The humidifier with a hygrostat constantly monitors the humidity of the air, and if it falls below the set value, it turns on, restoring the necessary microclimate. This is much more convenient than manually controlling the humidity.

— Air flow adjustment. A switch that allows you to set the desired level of airflow at the outlet of the humidifier. It plays the role of an intensity regulator: the higher the speed of the evaporator or fan, the more intensively the device works and the faster the desired humidity level will be reached. However, note that, unlike a hygrostat, this function does not automatically turn off when the desired humidity level is reached.

— Ionizer. A device for saturating the air with negatively charged ions. It is believed that the presence of such ions in the air has a beneficial effect on health and well-being, and also creates a feeling of freshness. In addition, ionization helps to reduce the amount of flying dust — it settles faster on various surfaces.

— Aromatherapy. A device for saturating the air in the room with pleasant smells at the request of the user. In humidifiers, aromatic oils can be added to the water for this purpose; in air purifiers, special replaceable cartridges are used....r>
— Ozonation. The function of saturating the air in the room with ozone. Ozone (a substance made up of three oxygen atoms) is a powerful natural disinfectant. In small quantities, it not only purifies the air of pathogenic bacteria but also creates a feeling of freshness. At the same time, an excess of ozone hurts well-being and can lead to serious diseases. So in some cases, ozonation is not just unnecessary, but also undesirable — especially if there are other sources of ozone in the room, such as laser printers or copiers.

— Night mode. A special mode of operation, designed for nighttime. Usually, in this mode, the device reduces the fan speed, thereby reducing noise. And some models in the night mode also maintain higher humidity levels than in the daytime — it is believed that this is the optimal microclimate for sleep.

— Warm steam. The function of preliminary heating of water; provided in ultrasonic and water models. By default, such devices produce "cold steam" at room temperature; it may contain pathogenic bacteria. To destroy them, the water in the tank can be preheated to temperatures of the order of 80-85 °C.

— Water purification. Water purification in humidifiers can be implemented in different ways, the most popular is the filtration cartridge, usually ceramic. It allows you to remove excess salts and other minerals, thereby softening the water and reducing the amount of deposits. This type of cleaning is predominantly used in ultrasonic humidifiers. In air washers, silver rods are more often used for water purification. Silver has antibacterial properties due to the formation of silver ions in water.

— Filter indicator. An indicator that indicates the need to clean or replace the filter. It is usually installed on expensive electronically controlled models. This feature is especially desirable for models with charcoal filters: at the end of their service life, such a filter begins to release harmful substances instead of absorbing them, and it is extremely important to replace them on time.

— Auto mode. The function used in devices with air purification capability (see "Type"). Devices with this function can independently monitor the state of the air and respond to it — turn it on when pollution is detected and turn it off after the air is cleaned. And some advanced models are even able to adjust the intensity of work to the level of pollution. Anyway, the auto mode saves the user from having to monitor the state of the air himself and enable/disable the cleaning programme. — Timer. The function that provides automatic shutdown after a user-defined time. It eliminates the need to turn off the device manually, which is not always convenient. The timer can be useful, for example, if the humidifier is turned on at night, or if it works in a children's room with a sleeping child who is not wanted to be disturbed.

— Automatic switch-off. In humidifiers with this function, a special sensor monitors the presence of water in the reservoir, and when it runs out, it turns off the device. It avoids wasted energy and, in steam models (see Type), also prevents overheating.

— Evaporator rotation. The ability to rotate the evaporator nozzle to change the direction in which steam is supplied. This function allows you to distribute the moisture produced by the device throughout the room as evenly as possible.

— top water fill. The ability to add water to the device from the top side — usually through a removed cover or a hole in the cover. Usually, humidifiers with this function can be refilled right during operation — this is more convenient than turning off every time, or even disassembling the device to add water. Among other things, this feature can be useful if the device is used in a children's room — it allows you to do it without unnecessary noise and not disturb the sleeping baby.

— Child lock. Usually, child lock means the ability to block device controls so that a curious little child cannot turn it on, turn it off or change settings on its own. Such a lock is disabled in a non-obvious way, accessible to an adult, but not to a child — for example, by simultaneously pressing two buttons.

— Display. The display makes the control of the device more convenient. The screen can display data on the current operating mode, the set timer, the status of the filter (in purifiers) or the water tank (in humidifiers), etc. Information about the status of humidity and temperature can also be displayed. Displays, usually, are equipped with expensive models with electronic control.

— Humidity indicator. The presence of a special indicator, mostly digital, allows you to show the level of humidity in the room.

— Temperature indicator. Similar to the dial described above, which displays not the humidity, but the temperature in the room.

— Air quality indicator. A function more related to air purifiers. With its help, you can understand how polluted the air in the room is and whether it needs to be cleaned. It can be achieved with the help of indicators — for simple models it lights up when the air condition is inappropriate, for more advanced ones it shines in different colours depending on the air quality.

— Control via the Internet. The ability to control the device via a smartphone, tablet or other gadget. Features of such control depend on the type of device (see above). So, in humidifiers and combined models, communication is carried out via Wi-Fi, and control access can be obtained not only on site but also via the Internet, from anywhere in the world. At the same time, both a special application for a mobile device and a page in a regular browser, which can also be opened from a computer, can be used for control; these details need to be clarified separately. Purifiers mainly use Bluetooth for communication, and only a gadget with an installed application can be a control device. However, this function can significantly make life easier for the user. And it's not just the ability of remote control: the application is often more convenient and intuitive than the classic control panel, and it can provide various additional features.

– Voice assistant. Device support for one or more voice assistants (assistants) such as Amazon Alexa, Apple Siri, and Google Assistant. Recall that the voice assistant is a service that allows the user to control various devices and receive various data using voice commands. However, it is not the built-in voice recognition system, but compatibility with an external gadget (phone, tablet, smart speaker) on which the corresponding assistant is installed. It is this device that will recognize the user's commands and transmit them to the humidifier/purifier. However, this control method is often more convenient than traditional options like a remote control or a mobile application.

— Remote control. A remote control is included with the device. The convenience of this function is obvious — it eliminates the need to approach the device every time to turn it on, turn it off, etc. Note that control from the remote control, unlike control via a smartphone (see above), is usually available only within direct visibility.

— Backlight. A decorative function that does not affect the main functionality. The illuminated body of the device looks beautiful in the dark and can even be used as a night light.

Maximum performance provided by the humidifier — that is, the maximum amount of air that it can pass through itself in an hour. This parameter is most relevant for models with a purifier function (see “Type”). However, it can also be specified for humidifiers.

The flow rate is selected by manufacturers, taking into account the area and, accordingly, the volume of the room for which the device is designed. For efficient operation, the device must be able to pass the entire volume of processed air through itself at least once per hour (or better, two or three times). At the same time, for models with the same area of the room, different air flow indicators can be declared - accordingly, the processing speed and efficiency will differ.

We also note that the recommended area of the room can be estimated by air flow if the latter is not stated in the specs. For example, if the device provides 200 m³/h, this means that the volume of the room can be no more than 200 m³, which, with a standard ceiling height of 2.5 m, gives an area of 200/2.5=80 m². And ideally, the area should be even 2-3 times smaller — that is, it should be about 25-40 m².

The noise level generated by the air cleaner when operating in low or night mode. Most of these devices are used in domestic conditions, so the noise level plays an important role, especially at night. According to sanitary standards, constant noise in such rooms should not exceed 40 dB (quiet conversation) during the day and 30 dB (wall clock ticking) at night. More detailed comparison tables and recommendations can be found in special sources.

The noise level generated by the air purifier during operation. Most of these devices are used in residential areas, so this parameter should be treated carefully. According to sanitary standards, constant noise in such rooms should not exceed 40 dB (quiet conversation) during the day and 30 dB (wall clock ticking) at night. More detailed comparison tables and recommendations can be found in special sources. It is also worth mentioning that the noise level is indicated for the maximum operating speed, so the noise level will be significantly lower in reduced mode.

It is the maximum power consumed by the device during operation. The lower it is the more economical the device. However, it is worth noting that in humidifiers, energy consumption is directly related to the principle of operation (see "Humidiation"): with similar characteristics, steam models are high consumption, where energy is spent on heating water, and the most economical are water models. Nevertheless, the energy consumption of modern humidifiers is generally low — even for steam humidifiers it rarely exceeds 600 W, and ultrasonic devices with similar power are already heavy industrial equipment. Purifiers also do not differ in consumption: a power of more than 100 W is rare among such devices.