Comparison Toshiba Seiya RAS-B07J2KVG/07J2AVG 20 m² vs Toshiba RAS-07BKV/07BAV-EE 20 m²

The British Thermal Unit (BTU) is used to indicate the rated capacity of air conditioners in cooling mode. The parameter is indicated mainly for split and multi split systems with wall installation. Capacity is indicated in BTU per hour, while 1 BTU/h is equal to about 0.293 watts. The rated capacity of an air conditioner is often a multiple of 1000 BTU. The indicator determines how many thousand BTU/h the air conditioning equipment provides. For example, the marking "9 BTU" here means a unit for 9000 BTU/h or about 2600 watts of effective capacity.

The practical meaning of the capacity is that by BTU you can easily determine the recommended area of a standard room in square meters: just multiply the figure indicated in the characteristics by 3. So, for 9 BTU it will correspond to 9*3=27 m². Note that there is no strict relationship between BTU and watts in this list: for example, air conditioners with an effective capacity of 2360 to 2900 W fall into the same category of 9 BTU. In practice, even such an approximate ratio is enough to understand which air conditioner should be considered for cooling certain area.

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.

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 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 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.

The seasonal energy efficiency class that the air conditioner complies with in cooling operation. Initially, this parameter was designated in letters from A(the most economical indicator) to G (the most expensive); however, more efficient classes than A appeared later — A+, A++ and A+++(the more pluses, the higher the energy efficiency).

This parameter is directly related to the value of the SEER coefficient. For more information on this factor and how it differs from the EER, see "Seasonal Cooling SEER Ratio". Here we note that each class has its range of SEER values; detailed correspondence tables can be found in special sources.

Other things being equal, more energy-efficient air conditioners are more expensive, but the difference can be recouped as it uses less electicity.