Room area (purification)
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.
Filters
Types of filters provided in the device with the purifier function (see "Type"). Some models allow you to install additional filters that are not provided in the standard configuration; however, for a full guarantee, it is better to immediately buy a device with the necessary equipment. Here are the most popular types of filters nowadays:
— Pre-filter. The filter installed first at the inlet to the device. Usually provides the simplest mechanical filtration from relatively large contaminants, for which it makes no sense to use more advanced and expensive solutions like HEPA or NANO elements (see below). And some devices are not equipped with any other filters at all, except for the pre-filter.
— Electrostatic filter. The action of such a filter is based on the property of the smallest particles in the air to acquire an electric charge and be attracted to an oppositely charged object. It provides effective cleaning from dust, smoke and soot; in addition, the air is also slightly ionized, which can also be attributed to the advantages (for more information about ionization, see "Features"). But with odours and harmful volatile substances, such a filter handles poorly. The design of an electrostatic filter is based on a set of metal plates that are charged; the plates need to be regularly cleaned of dirt, they do not require other maintenance, so the filter life is almost unlimited.
— HEPA filter. Dry fine filter. It is similar in design to co...nventional mechanical filters, but differs from them in terms of the principle of operation: dirt particles do not so much get stuck between the filter fibres as they stick to them. As a result, HEPA filters can retain contaminants that are much smaller than the gaps between the fibres, which ensures high filtration efficiency. Different types differ in quality. So HEPA 10 can capture at least 85%, HEPA 11 — 95%, HEPA 12 — 99.5%, HEPA 13 — 99.95% and HEPA 14 — 99.995%.
— NANO filter. Porous ultrafine filter. Detains particles with a size of thousandths of a micron (millionths of a millimetre), cutting off not only small mechanical impurities but also individual molecules of organic substances (although such a filter is still inferior to a charcoal one in terms of molecular purification efficiency).
— Charcoal filter. Filter based on activated carbon or other similar adsorbent. It can effectively retain volatile molecules of various substances, thanks to which it perfectly eliminates odours. On the other hand, the charcoal filter is demanding compliance with the service life: after the resource is exhausted, it not only loses efficiency but also becomes a source of harmful substances, so in such devices it is especially important to change the filter elements on time.
— Photocatalyst. The principle of operation of such a filter is to decompose the harmful substances that enter it into neutral components (mainly water and carbon dioxide) under the action of ultraviolet radiation and a special catalyst. It is not designed to remove mechanical impurities, but it does an excellent job of removing odours and harmful volatile impurities, and also effectively destroys bacteria and viruses. At the same time, the catalyst is not consumed during operation, and the reaction products evaporate on their own — so that the filter has an almost unlimited service life, while it practically does not require maintenance. The main disadvantage of photocatalysts is their high price.
— Antibacterial. Under this name, several types of filters are combined, designed primarily for the destruction of harmful microorganisms. So, some antibacterial filters use an active substance that destroys the protein shell of microbes, others use an ionizer or ozonizer, others use UV radiation, etc. So the specific features of such a filter and the rules for its maintenance should be clarified separately.
– Ultraviolet lamp. A lamp that processes passing air with UV radiation. This treatment provides a bactericidal effect: ultraviolet light neutralizes most bacteria, viruses and fungi.
In addition to those described above, modern cleaners may include other, more specific types of filters — for example, to neutralize formaldehyde or ozone, which can be useful in some types of industries.
Controls
The type of control provided in the device.
Note that mechanical and electronic devices can use the same elements - buttons, rotary knobs, sliders — and, as a result, almost do not differ from each other in appearance. The difference lies in the fact that the mechanical control directly affects the working part of the device (for example, when the knob is turned, the resistance of the rheostat that regulates the power changes), and the electronic control sends a signal to the control circuit, which accordingly changes the parameters of the device. The advantages of mechanical ones are simplicity, reliability and low cost. However, it allows you to adjust only basic functions, and the accuracy of the adjustments is low. In turn, with electronic control, various additional features can be provided and individual operation parameters can be very precisely adjusted. But such control is more complicated and expensive. Electronic control can also be performed in the form of touch controls, which gives the device elegance and elevates it to a more advanced level.
