Capacity
The nominal capacity of the dehumidifier is the maximum amount of moisture that the unit can remove from the air per day.
For efficient operation, the capacity of the dehumidifier must be no less than the amount of excess moisture that accumulates in the room during the same time. This amount can be calculated using special formulas or calculator programs. However, the results of such calculations are quite approximate, but they can be used in the selection, and for a full guarantee it is worth taking a performance margin of at least 10–20%. If desired, this margin can be more; but note that high performance significantly affects the price, dimensions and energy consumption of the dehumidifier.
As for specific values, entry-level models for small spaces provide
less than 25 L/day. Indicators of
26 – 50 L/day can be called average,
51 – 75 L/day — above average; there are also many powerful professional units with a capacity of
more than 75 L/day.
Power consumption
Power consumption of the dehumidifier in normal operation.
From a practical point of view, this characteristic is secondary — manufacturers select power in such a way as to provide the necessary operating parameters (performance, air flow, etc.), and when choosing, you should focus primarily on these parameters. However, certain practical points also depend on the power consumption. Firstly, only models of less than 3-3.5 kW can be connected to ordinary household outlets; higher power consumption will require either a 400 V supply (see Power supply) or a direct connection to the panel. However, even power of
more than 2 kW is rare in modern dehumidifiers — for most of these devices, the energy consumption is in the range
from 500 to 1000 W or
from 1000 to 2000 W, and in the most modest models it does
not exceed 500 W at all. Secondly, power data may be required to calculate the load on the power grid. Such a need arises mainly for the selection of additional equipment — circuit breakers, AVR, UPS, etc.
Also, note that models with similar performance may differ in power consumption. However, a more economical dehumidifier often costs more, but with regular use, this difference pays off by reducing energy costs.
Air flow
The maximum amount of air that a dehumidifier can pass through in an hour.
The choice for this parameter depends on the size of the room. It is believed that for effective operation, the dehumidifier must drive through itself an amount of air in an hour that exceeds the volume of the room by 3-4 times; and you can determine the volume of the room by multiplying the area by the height of the ceiling. For example, a 12 m² room with 2.5 m ceilings will hold 12*2.5=30 m³ of air; accordingly, for efficient operation in such a room, a dehumidifier with a capacity of 30*3=90 m³/h, and preferably 30*4=120 m³/h, is required. It is quite possible to choose a unit with a margin for airflow — unless you need to take into account that an increase in performance affects the price and energy consumption. But a too-low value of this parameter is undesirable: such a dehumidifier simply cannot effectively cope with its task.
As for specific figures, relatively low-power models produce
up to 250 m³/h, equipment for
251–500 m³/h and
501–750 m³/h can be attributed to the average level, and many units are capable of processing
more than 750 m³/h.
Operating temperature range
The ambient temperature range in which the dehumidifier can operate normally. The wider this range, the more versatile the dehumidifier is, and the more diverse the conditions in which it can be used. Note that, in contrast to the humidity range (see above), going beyond the operating temperatures is fraught not only with loss of efficiency but also with serious malfunctions and even breakdowns. Therefore, it is worth choosing a unit according to this parameter in such a way that it is guaranteed to block possible fluctuations in the temperature of the air with which the dehumidifier is to work.
Note that most modern models are designed to operate at positive temperatures, with the lower limit being on average about 4–5 °C. The only type of dehumidifiers that can operate at temperatures below zero are
adsorption dryers(see "Suitable for").
Noise level
The maximum noise level produced by the dryer during operation. The lower this number, the more comfortable the use of the unit will be; this is especially true for residential premises. For workshops, warehouses and other similar places, the noise level is not so critical — this type of climate control equipment is often installed in places where there are almost no people, or in the vicinity of such noisy equipment, against which the noise from the dehumidifier can simply be lost. However, for non-residential premises, data on the noise can be useful — for example, to assess the need for special ear protection and other labour protection measures.
Note that this parameter is measured in decibels, and this is a non-linear value: for example, a change of 3 dB approximately corresponds to an increase/decrease in power by 2 times, by 10 dB — by 10 times, etc. Therefore, to assess the noise level, it is easiest to use comparative tables. Here is a simplified table for the range that most modern dehumidifiers fall into.
35 dB — muffled conversation;
40 dB — quiet conversation; the maximum noise level allowed in residential premises during the daytime;
45 — 50 dB — conversation in a normal tone;
55 dB — background sound in the office without special noise sources;
60 dB — loud conversation;
65 dB — city street with average traffic intensity;
70 dB — a conversation of several people in raised tones.
