Comparison Ballu BDH-40L vs Ballu BDH-35L

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.

The type of control provided in the design of the dehumidifier.

The type of control determines how external control elements (buttons, knobs, sliders) interact with the hardware of the unit. There are two options here:

— Mechanical. Systems in which the control elements act directly on the individual parts of the dryer. For example, fan speed adjustment (see "Features") in such systems can be carried out using a slider that directly changes the resistance of the resistor in the fan power circuit; the shutdown timer (see ibid.) is a rotary knob with a clock mechanism, etc. The mechanical control is simple and reliable, it is suitable for all basic functions of the dehumidifier and at the same time, it is inexpensive. On the other hand, such systems are inferior in accuracy to electronic ones, and besides, they do not allow many additional features (remote control, display, etc.). Therefore, although this type of control can be found in all categories of dehumidifiers, there are fewer such models on the modern market than electronic ones.

— Electronic. Control is carried out through a special electronic circuit: each user action (pressing a button, turning a knob, etc.) is processed by this circuit, and from it control signals are sent to the working elements of the dehumidifier. Such systems are more functional and advanced than mechanical ones. Electronic control is conveni...ent and allows you to use various additional functions — for example, displays and remote controls; and individual parameters can be controlled with very high precision and small adjustment steps. The disadvantages of electronic systems are considered to be higher cost and lower reliability than mechanics, as well as repair difficulty. At the same time, these shortcomings are not so often critical: for example, differences in cost are usually almost imperceptible against the the overall price of devices, and the probability of failure in modern electronics is still very low. Nowadays, it is the most popular type of control among dehumidifiers of all categories. And it can be implemented either by buttons or by touch panel. The second option gives the device a solid look.

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.

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").

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.

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.

— Hygrostat. An automatic regulator that allows you to maintain a certain humidity in the room. Such a regulator constantly monitors the amount of moisture in the air and turns on the dehumidifier if this amount exceeds the set value, and when the humidity drops to the desired value, it turns off the unit. The hygrostat is especially convenient in those cases when it is necessary not to dry the air as much as possible, but simply to lower the humidity to a certain level. And since dehumidifiers are most often used precisely for such tasks, this function is also very popular in them — it is available in most models, regardless of the purpose.

— Fan speed adjustment. A regulator that allows you to change the speed of the fan built into the dehumidifier — and, accordingly, the actual value of the air flow (see above). This function allows you to adjust the air flow value — and therefore the performance of the unit — to the specific situation. For example, when there are a lot of people in the room, it makes sense to increase the speed; and if there are few or no people at all, you can reduce the fan speed, reducing power consumption and wear on the unit.

— Night mode. Special operating mode designed for night time. Usually, in this mode the device reduces the fan speed, thereby reducing noise.

— Ionizer. Ions...are electrically charged molecules. It is believed that the presence of negatively charged ions in the air has a beneficial effect on the health and general well-being of a person. To saturate the air with such ions, ionizers are used in dehumidifiers.

— Shutdown timer. The presence of a timer in the dehumidifier that turns off the device after a certain time set by the user. This function allows you to leave the dehumidifier on without worrying about its timely shutdown — this will happen automatically after the specified time has elapsed. The timer is indispensable in cases where you need to leave the room being dried, but there may not be an opportunity to return and turn off the dehumidifier manually — for example, if you need to close the pool at night, and the air humidity is still too high.

— Anti-freeze mode. A function that prevents excessive cooling of the dryer parts and the formation of a large amount of ice on them. Recall that all modern dehumidifiers (except for adsorption ones, see "Suitable for") have refrigeration systems — to remove excess heat generated during humidity concentration. In some cases, individual components of such systems can cool down strongly (down to sub-zero temperatures), which is undesirable both in itself and due to the formation of ice. To avoid this, the anti-freeze system constantly monitors the state of the evaporator and, if necessary, turns on the heating, preventing a critical drop in temperature and removing the ice that has formed.

— Drying clothes (turbo mode). The intensive air dehumidification mode with maximum performance of the device will come in handy when drying clothes and linen. It helps remove excess moisture during frequent washing. This ensures dehumidification without controlling the humidity level using a hygrostat (see the corresponding paragraph).

— Air filter. Built-in air filter, thanks to which the dehumidifier can further clean the air during operation. Note that the efficiency of such filters can be different — from the simplest systems for trapping dust and other mechanical contaminants to charcoal elements that can even cope with odours. This nuance, as well as the features of filter maintenance, should be clarified separately.

— Filter indicator. Indicator signalling the need to replace the working element in the air filter. Without timely replacement of consumables, the filter at best loses its efficiency, at worst it increases the load on the dehumidifier, or even starts releasing substances into the air instead of trapping them. Replacement indicators may differ in functionality. However, this function significantly reduces the likelihood of missing the next filter maintenance period.

— Tank indicator. An indicator showing the amount of water in the condensate collection tank. The simplest version of such an indicator is a transparent insert in the tank wall, which allows you to monitor the amount of water without opening the tank once again; there are also more advanced systems, up to electronic sensors with display readings. However, anyway, the tank indicator makes it much easier to keep track of the amount of water and reduces the likelihood of missing a critical fill level.

— Auto shutdown. A system that monitors the amount of water in the condensate tank and automatically switches off the dehumidifier when this amount reaches a critical value. It avoids both floods and breakdowns of the unit itself.

— Drainage. Possibility of permanent removal of water, "extracted" from the air, outside the device (for example, directly to the street through a special tube). It allows you to simplify the cleaning of the water tank or do without it at all, which has a positive effect on the dimensions and weight of the dehumidifier. In addition, it makes it possible to work almost continuously, without interruptions to empty the tank with collected water, which is especially important for models used in swimming pools (see "Suitable for").

— Drain pump. Pump for forced drainage from the water tank. Often, the presence of a pump is justified in industrial dehumidifiers, when it is necessary to organize the removal of drainage on an ongoing basis (including, if necessary, its removal to a height of up to several metres).