Type of bearing
The type of bearing installed in the fan.
The bearing is a part that secures the rotating part of the fan to the stationary part and reduces friction between these parts. By type, it can be as follows:
— Plain bearing. The action of such bearings is based on the friction between two conjugated, that is, directly pressed one to the other over the entire area, surfaces. However, these surfaces are in contact with each other relatively weakly — between them is a layer of lubricant that reduces friction. In addition, to reduce resistance, rubbing parts are usually carefully polished and made of anti-friction materials. The main advantage of plain bearings is the simplicity of design and the resulting low cost. However, such parts are less durable than ball bearings, and they create more noise.
— Ball bearing. The principle of operation of a ball bearing is that a set of balls is placed between its movable and stationary parts, which roll inside during movement. Compared to plain bearings, such bearings last much longer, and they create less noise during operation. On the other hand, fans with similar equipment are noticeably more expensive.
Air flow (extraction)
This parameter describes the amount of air that the fan can pass through itself per hour when operating in extraction mode (see "Type"). It is one of the key characteristics of any extractor fan — it characterizes the overall performance and suitability of the unit for a particular room.
When choosing a fan for
maximum performance, two main indicators must be taken into account — the volume of the room and the air flow rate. The volume can be found by multiplying the area of the room by the height of the ceilings: for example, for a room of 12 m² in a residential apartment with standard ceilings of 2.5 m, this figure will be 12x2.5=30 m³. The air flow rate describes how many times per hour the air in an enclosed space must be completely replaced for ventilation to be sufficiently effective. This multiplicity is different for different types of premises: in particular, for the kitchen, it is 6-8, for the bathroom — 8-10, etc. More detailed values be found in specialized sources, in particular, sanitary standards. And the minimum required fan performance is calculated by multiplying the air volume by the air exchange rate. For example, if we have a bathroom with an area of 4 m² with the same ceiling of 2.5 m, then the volume of air in it will be 4x2=10 m³; Considering that the minimum air exchange rate for bathrooms is 7, for this room we need a fan with a capacity of at least 70 m³/h.
Rotational speed
The nominal fan speed during operation.
The rotational speed is one of the factors affecting the performance and, consequently, the overall efficiency of the fan. At the same time, this factor is far from being the only one. A lot also depends on the design of the blades, their number, the diameter of the impeller, etc. Therefore, fans with the same speed can differ significantly in capabilities, and you should pay attention primarily to performance.
At the same time, the rotation speed still has a certain practical significance. On the one hand, faster fans produce more noise; this drawback can be compensated to a certain extent by design tricks, but they, in turn, noticeably affect the price. On the other hand, to ensure the desired level of performance, lower-speed fans must either have impellers of a larger diameter (which accordingly affects the dimensions, and in most cases, the installation size) or, again, use design tweaks that affect the price.
Noise level
The noise level reproduced by the fan in normal operation.
The
lower the noise level, the more comfortable the use of the fan will be, the better it is suitable for rooms in which it is desirable to keep silence. In addition, there are certain regulations written in sanitary standards (for example, for residential premises during the day, a constant noise level of up to 40 dB is considered acceptable, and at night — up to 30 dB).
When choosing according to specific values recorded in the characteristics, it should be taken into account that the decibel used to measure the noise level is not a linear quantity: for example, an increase in sound power by 2 times corresponds to an increase of 3 dB, 10 times — by 10 dB, 100 times — by 20 dB. Therefore, to assess the noise level, it is easiest to refer to comparative tables, where the correspondence of specific values in decibels to various real sound sources is recorded. In most modern fans, noise is between 20 and 60 dB, here is the simplest table for this range:
20 – 25 dB — a weak audible sound, comparable to a whisper at a distance of 1 – 2 m;
25 – 30 dB — intelligible whisper at a short distance, ticking of a wall clock;
35 dB — muffled conversation;
40 – 45 dB — normal human speech;
50 – 55 dB — talking in raised tones, noise in the office;
60 dB — loud conversation at a distance of several metres.
Note that patter
...ns over 50 dB are rare; usually, these are “industrial” class units with a 400 V power supply and a large mounting diameter (see above), not intended for residential premises.Country of origin
The country specified as the manufacturer of the fan. Note that in most cases, this paragraph indicates the country of origin of the brand under which the unit was released. This country may not coincide with the place of production of individual components, or even with the final assembly place, and often such information is just a marketing ploy that plays on national stereotypes — for example, many consider German technology to be more reliable than Chinese. At the same time, these stereotypes are gradually losing relevance — in particular, due to the transfer of production mentioned above; and it makes sense when choosing to focus on reviews of real customers and the reputation of a particular brand, rather than on its national identity.
Now the following producing countries are represented on the market:
Germany,
Spain,
Italy,
China,
Latvia,
Lithuania,
Norway,
Poland,
Sweden.
Cover height
The size of the decorative fan cover in height.
For details on the features of such panels in different types of fans, see "Cover diameter". The same size is indicated in cases where the panels are in the shape of a square or rectangle (see "Cover shape").
Cover thickness
The size of the decorative fan cover in thickness.
This parameter describes how much such a panel protrudes above the surface of the wall or ceiling on which the fan is installed. For more information about the general features of decorative panels in different types of fans, see "Cover diameter".
Cover material
Manufacturers are actively innovating in the design of this part of the device. First of all, it is worth highlighting the various materials of execution, each of which has its advantages. And in particular, cheaper, but
plastic covers of various shapes, stylish and strict
metal covers, elegant and sophisticated
glass covers(
plexiglass is also found) and, of course, exclusive
wooden ones. More details about each:
— Plastic. Plastic covers are easy to process at the production stage and are inexpensive. At the same time, plastic is quite durable and practical. Such surfaces can be given almost any shade and colouring, due to which there is a wide variability of exhaust fans with a plastic cover. The disadvantages of this material include perhaps relatively low strength and sensitivity to scratches. However, such problems are rarely encountered due to the peculiarities of the placement of extractor fans.
— Stainless steel. Stainless steel is a high-strength material that resists scratches and looks stylish and rich. The stainless steel covers increase the reliability of the extractor fan housing and allow it to harmoniously fit into a modern interior. There are design options as a solid sheet of stainless steel and panels with decorative perforations. Metal covers are usually expensive,
...so there are relatively few such models. The vast majority of them belong to the premium class and are intended for interiors of the appropriate level.
— Glass. Glass covers are a design highlight of the design of extractor fans. This material is easy to clean and does not give in to scratches, has a shiny gloss or has a discreet matte structure. Glass covers in extract fans can be painted in a variety of colours, which allows you to choose the right model for the interior design concept of the room. Glasses for the front panel are often made tempered — there is no need to worry about the fragility of this material.
- Wood. Quite a rare material for exclusively decorative purposes. Such covers are harmoniously combined with interiors in a certain style — for example, with wooden walls, rooms in an "eco" design, baths or saunas. However, from a practical point of view, they do not have advantages over the same plastic ones but are noticeably more expensive. Today, wooden covers are rather exotic, designed for principled adherents of natural materials.
- Plexiglas. A more advanced and durable analogue of plastic. Plexiglas usually have a translucent glossy finish with a characteristic sheen in the light. As a rule, such panels are made monophonic. They best fit in with the minimalist interiors of the premises. This option can be found in models of a strong middle level and top class.
— Aluminium. This material can be attributed to a confident middle class: aluminium is lightweight, has high strength, and is characterized by durability and resistance to corrosion. In addition, aluminium can be easily polished at the production stage, which simplifies the manufacturing process of aluminium covers. Extractor fans with such a front panel look stylish and expensive.Mounting depth (duct)
Mounting depth of the fan with a standard installation method.
This parameter describes how deep into the duct the unit (or its parts in the case of surface-mounted models, see "Type") is placed during installation. Knowing the mounting depth, it is possible to assess the suitability of the selected model for a particular installation location: a flat section at the very beginning of the duct must be no less than the installation depth of the selected fan.
The smallest value of this parameter is typical for some overhead models of fans: in them, the main part of the structure is outside, and usually, only 2-3 centimetres are required for installation. And most of all, hidden units require space (see "Type").