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.
Recommended room area
The area of the room for which the device is designed. It is the maximum area that this model can effectively handle: the use in smaller rooms is quite acceptable, but the device simply does not have enough performance for a larger space. Also, note that the area is indicated based on a ceiling height of 2.5-3 m — the standard value for residential premises; with a higher ceiling height, the effective area decreases, and it can be recalculated using special formulas.
When choosing by area, it is worth taking a certain margin, but it should not be too large — otherwise, the device will be unnecessarily powerful, bulky and expensive.
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.
Condensate tank volume
The volume of the tank for collecting condensate (moisture removed from the air), provided in the design of the dehumidifier.
The larger the condensate tank, the slower it will fill up and the less often it will have to be emptied. It is especially important for high-performance units (see above). On the other hand, the volumetric tank has the appropriate dimensions, which affects the dimensions of the entire dryer. When evaluating the relationship between tank capacity and dehumidifier performance, note that the device rarely operates at full capacity. See "Dehumidification capacity" for more on this; here we note that if, for example, a dehumidifier with parameter of 24 L/day has a tank of 4 litres, this does not mean that the tank will necessarily be filled to the top every 4 hours. An alternative to tanks is the use of permanent condensate drainage systems; see "Features" for details.
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.
