Comparison Daikin Sensira FTXF25A/RXF25A 25 m² vs Daikin Sensira FTXB25C/RXB25C 25 m²

Additional features provided by the device.

— Inverter control. The presence of a compressor with inverter power control in the air conditioner. Models without an inverter have only two modes of operation — full power and off, and the set intensity of heating/cooling is provided by turning the compressor on and off for certain periods. In turn, the principle of inverter control is to smoothly change the compressor power, which avoids constant switching on and off. It provides several advantages: minimal wear, no power surges and unnecessary load on the mains, as well as a comfortable (low and stable) noise level. The main disadvantage of inverter models is the rather high cost.

— Timer. A function that allows you to set the time for automatic shutdown of the air conditioner. Thanks to the timer, you can, for example, start the air conditioner before going to bed and fall asleep peacefully without worrying about turning off the device — it will turn itself off after a user-defined time. And in some models, the timer is part of the night mode (see below).

— Auto restart. Automatic restoration of air conditioner settings after a power outage. Simply put, when power is restored, a device with this function will continue to operate in the same mode as before the power outage.

— Air pollution sensor. A sens...or that monitors the presence of smoke, dust and other contaminants in the air passing through the air conditioner. The use of such a sensor can be different: some models can independently start the ventilation mode when pollution is detected, in others the sensor is only responsible for automatic shutdown, and ventilation must be turned on manually. However, this function greatly facilitates the monitoring of air quality.

— Motion sensor. A sensor that monitors the presence of people in the room. Using the location of people in the room, the air conditioner can change the direction of the flow away from people, thereby protecting against drafts. If the presence of people is not detected, then the air conditioner may switch to low power consumption mode and work not at full capacity, maintaining a comfortable temperature, and depending on the implementation of this functionality, it may even turn off if there is no activity in the room for a long time. It helps to save energy and provides an additional guarantee in case the user forgets to turn off the air conditioner manually.

— Vertical blinds drive. Recall that in most models the air outlet has the form of a slot, equipped with two types of blinds — horizontal (usually one), along the length, and vertical, along the height. By default, the motor drive has only a horizontal blind: this allows you to change the direction of the airflow vertically, as well as close the duct during non-working hours. However, some modern air conditioners (mostly wall-mounted, see "Installation") also provide a vertical blinds drive — it allows you to turn them from side to side, changing the direction of the horizontal airflow. It significantly expands the possibilities for setting up the unit for the specifics of the situation.

— Self-diagnosis. The ability to automatically detect malfunctions and errors in the operation of the air conditioner. The specific features of the operation of this function may be different: in some models, the “health” of the unit is constantly monitored or automatically checked at certain intervals, in others, such a procedure is only started manually. Usually, self-diagnostic systems can automatically fix minor problems that do not require external intervention. More serious problems are reported to the user by the device, for example, by an error code on the display.

— Control via smartphone. The ability to remotely control the air conditioner from a smartphone or other similar device, such as a tablet. Usually, for this, you need to install a special application on the device. Such control can be more convenient and intuitive than using the remote control — the application can provide various specific parameters and functions that are not available for the remote control (for example, the schedule of work by day of the week). In addition, through the application, you can monitor the operating parameters of the air conditioner in real time — the set temperature, speed, programme, etc. — and receive notifications of problems. And some models with this feature can even be connected to the Internet — and get access to air conditioning control from anywhere in the world where there is access to the World Wide Web. Connection with the control gadget can be carried out via Bluetooth or Wi-Fi, depending on the model. For some devices, this feature may require the use of an external Wi-Fi module (see below).

— Wi-Fi module connect. Such equipment significantly expands the functionality: a Wi-Fi connection can be used to control via a smartphone or even via the Internet, to transfer statistics and other service data to external devices (smartphone, laptop, etc.), for remote diagnostics and troubleshooting, etc. The specific set of capabilities associated with the wireless module should be specified separately; however, this feature is typical mainly for fairly advanced models. Note that modern air conditioners can be equipped with built-in Wi-Fi modules. However, when buying such a model, you have to immediately pay extra for additional communication options, while with a separate Wi-Fi adapter, there is a choice — you can buy it both together with the air conditioner, and separately, later (or even not buy at all if this function turns out to be unnecessary).

— I Feel (remote control with temperature sensor). The presence of a temperature sensor in the complete remote control. Usually, such a remote control also has a separate button, when pressed, the air conditioner measures the temperature at the location of the remote control, that is, near the user. It allows you to more accurately control the microclimate than when using a sensor on the indoor unit — the device estimates the temperature at the user's location, and not at the installation site of the indoor unit.

Power consumption of the air conditioner in cooling and heating mode; for models without a heating mode, only one number is given. This parameter should not be confused with the effective capacity of the air conditioner. Effective capacity is the amount of heat that the unit can "pump" into the environment or the room. This item also indicates the amount of electricity consumed by the device from the network.

In all air conditioners, the power consumption is several times lower than the effective capacity. It is due to the peculiarities of the operation of such units. At the same time, devices with the same efficiency may differ in power consumption. In such cases, the more economical models usually cost more, but with continued use, the difference can quickly pay off with less electricity consumption.

Also, two points related to electrical engineering depend on this nuance. Firstly, power consumption affects power requirements: models up to 3 – 3.5 kW can be connected to a regular outlet, while higher power consumption requires a three-phase connection (see below). Secondly, the power consumption is needed to calculate the load on the mains and the necessary parameters of additional equipment: stabilizers, emergency generators, uninterruptible power supplies, etc.

The amount of air that an air conditioner can pass through itself in an hour.

This parameter depends on the power and the overall level of the device, but there is no strict dependence here: models with the same effective capacity may differ in air circulation speed. In such cases, it is worth proceeding from the fact that a higher speed contributes to uniform cooling/heating of the air and reduces the time required to create a given microclimate; on the other hand, higher-performing air conditioners use more energy, are larger and/or cost more.

The maximum and minimum level of noise produced by the air conditioner during operation; for split and multi split systems (see "Type"), by default, it is indicated for the indoor unit, and the data for the outdoor unit can be specified in the notes.

The noise level is indicated in decibels; this is a non-linear unit, so it is easiest to evaluate this parameter using comparative tables — they can be found in special sources. Here we note that, according to sanitary standards, the maximum level of constant noise for residential premises is 40 dB during the day and 30 dB at night; for offices, this figure is 50 dB, and in industrial premises higher volume levels may be allowed. So it is worth choosing an air conditioner according to this indicator, taking into account where and how it is planned to use it.

As for specific numbers, among the quietest modern air conditioners, there are models with a minimum performance of 23 – 24 dB, 22 – 21 dB, and sometimes even 20 dB or less. However, units at 31 – 31 dB and 33 – 34 dB are not uncommon; such loudness, usually, does not create discomfort in the daytime, but at night it is no longer desirable. However, in some cases, a louder air conditioner may be the best choice: noise reduction affects the cost, sometimes quite noticeably, and if the device...is not planned to be turned on at night, you can not overpay for additional noise reduction.

The type of refrigerant used in the air conditioner.

The refrigerant is a volatile liquid that transfers heat between the outdoor unit(s) and the indoor unit(s). In common parlance, such compounds are also called freons, although this is not entirely technically correct. The type of refrigerant is most important when buying air conditioner units separately — for example, to assemble a multi split system (see "Type"): all units must use the same type of freon, otherwise they will be incompatible. However, there are quite noticeable physical differences between different compositions, sometimes quite important.

The most common refrigerants nowadays are R22, R32, R407C, R410A, R134A and R290, here is a more detailed description of them:

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

— R32. A fairly advanced refri...gerant that combines three key advantages: efficiency, environmental friendliness and uniformity. So, air conditioners under R32 can be made quite compact and, at the same time, powerful; this substance does not destroy the ozone layer and does not have a significant effect on global warming; and a homogeneous composition allows you to refuel the air conditioner without problems in case of a leak. The main disadvantage of models with this type of refrigerant is the high price associated not so much with the cost of the R32 itself but with the specific requirements for the design of the refrigeration circuit.

— 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 filler is zeotropic (heterogeneous in composition): its components have different boiling points and different evaporation rates. As a result, even with a small leak, the refrigerant loses its properties, and the situation can be corrected only by a complete refilling of the air conditioner.

— R410A. Another green alternative to R22. Unlike R407C, it is azeotropic — it consists of components with the same evaporation specs; so in the event of a leak, the ratio of these components does not change, in which case refilling the circuit is allowed instead of completely replacing the contents. 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.

— R134A. One of the modern refrigerants 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 composition is 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 quite rarely.

Cooling factor EER provided by the air conditioner. It is calculated as the ratio of the useful operating power of the air conditioner in cooling mode to the electricity consumption. For example, a device that delivers 6 kW of operating power in cooling mode and consumes 2 kW will have an EER 6/2 = 3.

The higher this indicator, the more economical the air conditioner is and the higher its cooling energy efficiency class (see below). Each class has its clear requirements for EER.

It is worth noting that this indicator is considered not very reliable, and in the European Union another coefficient has been introduced that is closer to practice — SEER. See Energy efficiency SEER (cooling) for more details.

The heating coefficient COP provided by the air conditioner. It is calculated as the ratio of the heat output of the air conditioner in heating mode to the electricity consumption. For example, if a device consumes 2 kW and produces 5 kW of thermal power, then the COP will be 5/2 = 2.5.

The higher this indicator, the more economical the air conditioner is and the higher its energy efficiency class when heating (see below). Each class has its own clear COP requirements.

Note that COP values are usually higher than the values of another important coefficient — EER (see above). It is due to the technical features of the air conditioners.

It is also worth mentioning that since 2013, a more advanced and closer-to-practice coefficient, SCOP, has been put into use in Europe. See "Energy efficiency SCOP (heating)" for more details.

The general energy efficiency class that the air conditioner complies with in cooling mode.

This parameter is indicated by letters from A (highest efficiency) and beyond. It is directly related to the value of the EER factor (see "Cooling EER"): each energy efficiency class corresponds to a certain range of factors (for example, B — from 3.0 to 3.2). Specific coefficient values for each class can be found in special tables; here we note that more efficient air conditioners are more expensive, but this difference can pay off due to less electricity consumption.

The general energy efficiency class that the air conditioner corresponds to when operating in heating.

This parameter is indicated by letters from A (highest efficiency) and beyond. It is directly related to the value of the COP coefficient (see "Heating COP"): each energy efficiency class corresponds to a certain range of coefficients (for example, C — from 3.2 to 3.4). Specific coefficient values for each class can be found in special tables; here we note that more efficient air conditioners are more expensive, but this difference can pay off due to less electricity consumption.