Comparison Midea AG-07N8C2F-I/07N8C2F-O 20 m² vs Midea Forest AF-07N1C2 20 m²

Cooling and ventilation modes are in each model by definition. But air conditioners with humidification are relatively rare. For them, the opposite format is mandatory — dehumidification and heating.

- Cooling. The mode of lowering the air temperature in the room is the main function of any air conditioner. Note that conventional air conditioners, when cooled, also remove moisture from the air. However, due to a decrease in temperature, the relative humidity in this mode changes slightly (or does not change at all).

- Ventilation. The mode in which the air conditioner provides only air circulation throughout the room, without changing its temperature and humidity. Such a function can be useful, for example, for air mixing and temperature equalization; in addition, when passing through the air conditioner, the air is filtered, which is useful, for example, for cleaning from dust and smoke, or for ensuring hygiene in a room where a sick person is. Let us emphasize that ventilation must be distinguished from the fresh air intake(see "Functions"). The ability to add air from outside is rare and only in expensive models of air conditioners.

- Dehumidification. Mode for removing excess moisture from the air. This function works by condensing water vapour on the cold heat exchanger of the air conditioner; the collected mo...isture is usually removed to the outside through a drainage tube or accumulates in a special reservoir. Note that condensation also occurs in the cooling mode (see above); the dehumidification mode differs from it in that the temperature of the air passed through the air conditioner changes very slightly — usually by no more than 1 °C — but the humidity drops very noticeably.

— Heating. The mode of increasing the air temperature in the room. It should be borne in mind that most air conditioners with this function are not designed to be used as full-fledged heating systems - their task is to "help" such systems, as well as heating in the off-season, when the main heating does not work. In addition, the permissible outside temperature (see “Minimum t for heating mode”) can be different: for example, not every unit with a heating mode can work in cold weather. On the other hand, there are exceptions - powerful cold-resistant models, approaching the characteristics of heat pumps and withstanding temperatures of -25 ° C and even lower.

- Humidification. A need to increase air humidity often arises in winter. When the air is heated by heating devices, its relative humidity decreases (and the overall comfort in the room is associated precisely with relative humidity). In addition, in rooms where there are small children, it is recommended to specially humidify the air. The humidifying mode in air conditioners is rare and only in premium models. And for the operation of the humidifier, a supply of water is required, which must be monitored and periodically replenished.

— Fresh air intake. Ability to mix fresh air from outside with the air passed through the conditioner. Thus, models with this function not only change the temperature and humidity of the air but also additionally refresh it. On the other hand, mixing significantly complicates both the design of the air conditioner itself and its installation. Therefore, this function is rare, and mainly in models of the middle level and above.

— Automode. A function that relieves the user of the need to manually control the parameters of the air conditioner. It is enough just to set the desired microclimate in the room. After that, the unit will independently monitor the current conditions and select the desired operating mode. Most often, this function provides temperature monitoring and automatic switching between cooling and heating but advanced models may provide more advanced features, such as humidity monitoring with automatic dehumidification or even humidification.

— Night mode. A function that allows you to use the air conditioner as comfortably as possible at night. There are two main features of this mode. First, the fan speed is set to a minimum, which reduces noise and avoids strong air currents that can disturb sleepers. Secondly, the temperature change occurs very slowly and smoothly — by a couple of degrees within two to three hours; this is considered optimal for sleep. Additionally, in the night mode, a timer can be provided that turns off the air conditioner after 7-8 hours.

— Emergency heating. A function found in air conditioners with heating (see "Operating modes"); is intended mainly for summer cottages and other similar places that can be left unattended for a long time during the cold season. When using standby heating, the air conditioner maintains a low positive temperature in the room (about +8..10 °С). It is enough to avoid freezing of walls and damage to communications, and at the same time, energy consumption is low.

— Self-cleaning. The mode of automatic cleaning of the internal parts of the air conditioner — usually due to intensive purging with air. It allows you to remove the accumulated dust inside and dry out excess moisture and also prevents the growth of harmful microorganisms. At the same time, self-cleaning does not eliminate the need for full manual cleaning or replacement of working elements in the air conditioner filters.

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 power provided by the air conditioner in heating mode. It is indicated by the amount of thermal energy that the air conditioner can "pump" from the external environment into the room when operating in this mode. The most modest modern units have a heating capacity of 2 – 3 kW or even less, in the most performant it reaches 6 – 8 kW or more.

When evaluating this capacity, the same formulas are relevant that are used in calculating the power of traditional heating. So, for the full heating of an ordinary residential or office space (with ceilings of 2.5-3 m and normal thermal insulation), a thermal power of at least 100 W is required. There are more detailed calculation rules that allow you to calculate the necessary characteristics for other conditions. And if we are talking about a separately sold outdoor unit (see "In box"), then the meaning of this parameter is somewhat different. It indicates the maximum power of the indoor unit that can be connected to this outdoor unit to work in heating mode. For multi split systems, respectively, the total capacity of all indoor units is taken into account.

Recall that most air conditioners are not designed for use as full-fledged heating systems. However, such a unit can be a good addition to the main heating system. At the same time, air conditioners are less expensive than el...ectric heaters: the heater has an effective power equal to energy consumption, and the air conditioner consumes much less energy than it supplies to the heated room.

Also note that the unit BTU (more precisely, BTU/hour) can also be used to indicate the effective capacity (including in heating mode). 1 BTU (BTU/h) initially corresponds to 0.293 W, and the numbers in the characteristics of air conditioners correspond to thousands of BTU/h. For example, a 7 BTU air conditioner will produce an effective capacity of 7000 BTU/h, or about 2 kW. Such marking is convenient because BTU can easily determine the recommended area of a standard room (in m2): just multiply the figure indicated in the characteristics by 3. So, in our example, the power of 7 BTU will correspond to an area of 7*3=21 m2.

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.

The seasonal SEER cooling factor provided by the air conditioner.

The meaning of this parameter is similar to the cooling coefficient — EER (see above): we are talking about the ratio of useful power to spend, and the higher the coefficient, the more efficient the device is. The difference between these parameters lies in the measurement method: EER is measured for strictly standard conditions (outside temperature +35 °C, workload 100%), while SEER is closer to reality — it takes into account seasonal temperature fluctuations (for Europe) and some other specific points, such as the increased efficiency of inverter compressors. Therefore, since 2013, it is customary to use SEER as the main parameter in the EU; this parameter was also adopted for air conditioners supplied to other countries with a similar climate.

Seasonal heating coefficient SCOP provided by the air conditioner.

Like the COP (see above), this parameter describes the overall efficiency of the air conditioner in heating operation and is calculated by the formula: thermal (useful) power divided by electricity consumption. The higher the coefficient, the more efficient the device, respectively. And the difference between COP and SCOP is that COP is measured under strictly standard conditions (outside temperature +7 °C, full workload), and SCOP takes into account seasonal temperature fluctuations (for Europe), changes in air conditioner operating modes, the presence of an inverter and some other options. Thanks to this, SCOP is closer to real indicators, and since 2013 this coefficient has been taken as the main one in the territory of the European Union. However, this parameter is also used for air conditioners supplied to other countries with a similar climate.