Comparison Trotec TTK 355 S vs Master DH 772

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.

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.

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 range of relative humidity (RH — relative humidity) of the ambient air, in which the dehumidifier is guaranteed to be able to cope with its task and at the same time perform at the level claimed by the manufacturer.

The wider this range — the more versatile the unit, the less likely it is to be in emergency conditions. At the same time, when choosing, it is worth considering the specifics of the application of the dehumidifier. Thus, dehumidifiers are initially designed for high humidity, but the ability to work at 100% relative humidity is not always required. For example, in the cold season, the air coming from the street is "drier" by itself when heated indoors (due to the increase in temperature, the relative humidity drops, although the actual amount of moisture in the air does not change), and even in wet weather, a dehumidifier with a limit of 80-90% may be enough. And the lower dehumidification limit directly depends on the tasks facing the device. If we are talking about living quarters, offices and other places where you need to create conditions that are pleasant for people, then you need to take into account that the most comfortable values for a person concerning humidity are 40-70%. Therefore, for such conditions, it makes no sense to specifically look for a device with a lower limit of less than 40%. But for specific tasks such as drying rooms during repairs, warehousing, etc. lower humidity levels may be needed.

Note that many model...s are quite capable of working outside the operating range, except that the performance may decrease. However, it does not hurt to clarify such an ability according to the official documentation.

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.

The type of refrigerant used in the dehumidifier.

A refrigerant is a special substance (most often freon), which circulates through the cooling circuit in dehumidifiers with a condensing principle of operation (and these are all varieties, except for adsorption ones — see "Suitable for"). This substance provides the removal of excess heat generated during condensation of moisture. The type of refrigerant primarily determines the technical features of its application, such as the possibility of partial replacement and the requirements for the strength of the cooling circuit.

In modern dryers, you can mainly find brands of refrigerants such as R22, R407C, R410A, R134A, R290 and R32. Here is their general description:

— R22. The most "old" of the varieties of refrigerant found nowadays. It is distinguished by low cost, low operating pressure (which has a positive effect on the reliability and price of the cooling circuits themselves) and uniformity of composition, which allows, in case of a refrigerant leak, not to change it entirely, but simply to replenish the system with the required amount of liquid. However, R22 is environmentally unsafe (mainly for the ozone layer), which is why it is gradually being replaced by more ad...vanced compounds.

— R32. A fairly advanced refrigerant that combines three key advantages: efficiency, environmental friendliness and uniformity. Dehumidifiers with R32 can be made quite compact and, at the same time, performant; this substance does not destroy the ozone layer and does not have a significant effect on global warming. The main disadvantage of models with this type of refrigerant is the high price.

— R407C. A refrigerant designed as a safe alternative to R22; does not affect the ozone layer. At the same time, such a composition is much more expensive; its working pressure is slightly higher, which requires a greater strength of the cooling circuit (although not as high as for R410A); and polyester oil used with R407C tends to absorb moisture and lose properties. In addition, this refrigerant is zeotropic (heterogeneous in composition): its components have different boiling points and evaporation rates. As a result, even with a small leak, the composition of the refrigerant and its properties change, and the situation can be corrected only by a complete replacement of freon.

— R410A. Another "green" alternative to R22. Unlike R407C, it is azeotropic — it consists of components with the same evaporation characteristics; so that in the event of a leak, the ratio of these components does not change, in which case refilling of the circuit is allowed instead of a complete replacement of freon. On the other hand, R410A is characterized by high operating pressure, which puts serious demands on the strength and reliability of the cooling circuit and increases its cost; and the refrigerant itself is quite expensive.

— R454C. Hydrofilin-based refrigerant is considered environmentally friendly and environmentally friendly, positioned as another option to replace the outdated R22 and an alternative to R407C. The composition is a mixture of R32 and R1234YF.

— R134A. One of the modern freons with advanced properties. It is completely homogeneous, like R22, but at the same time, it is safe for the ozone layer and is characterized by a low coefficient of influence on global warming. The disadvantage of this refrigerant is its traditional — high cost; in addition, it uses polyester oil, which is prone to moisture absorption.

— R290. Liquefied propane is used as a refrigerant. It has several advantages: non-toxic, environmentally friendly (zero impact on the ozone layer, minimal impact on global warming), homogeneous (i.e. does not require complete replacement in case of leakage, it is enough to replenish the missing amount), used with mineral oil, which is insensitive to moisture. In addition, propane has a low operating pressure, which simplifies the design of circuits and reduces their cost, as well as a low temperature at the outlet of the compressor, which contributes to efficiency. This refrigerant has two disadvantages: flammability and high compressor power requirements, which makes such units quite heavy and bulky. Therefore, despite all the advantages, R290 is used relatively rarely.

— 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).