Power consumption
The maximum power consumed by the fan during operation. The higher the power consumption, the higher, usually, the greater the airflow rate created by the fan, and, accordingly, the higher the performance of the device. On the other hand, power usually directly affects the price, all other things being equal.
Number of speeds
The number of preset speeds at which the fan blades can rotate. The rotation speed is usually set by pressing the corresponding button (in addition, there is also a stepless adjustment, see the relevant paragraph). Most modern models with step adjustment have three preset speeds.
Air flow
The maximum performance provided by the fan — that is, the maximum amount of air that it can pass through itself in an hour.
The air flow 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. At the same time, for models with the same area of the room, different performance parameters can be claimed — accordingly, the processing speed and efficiency will differ.
Also, note that the recommended area of the room can be estimated by performance if the latter is not stated in the characteristics. For example, if the device provides 200 m³/h, this means that the volume of the room can be less 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, be about 25-40 m².
Maximum noise level
The maximum noise level produced by the fan when operating at the highest speed. For comparison: a noise of 30 dB corresponds to a distinguishable whisper at a distance of 5 m, 40 dB — to human speech, and 50 dB — to the sound background in an office room. The quieter the fan runs, the more comfortable it is to use.
