Nominal capacity BTU
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.
Power consumption (cooling/heating)
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.
Noise level (max/min)
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.Cooling EER
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.
Heating COP
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.
Energy efficiency EER (cooling)
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.
Energy efficiency COP (heating)
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.
Display
A small screen installed on the indoor unit of the air conditioner. Such
a display usually has basic functionality and displays a limited set of characters - numbers, some letters, sometimes also individual graphic icons. However, even such a screen can display quite a variety of information: set temperature, operating mode, timer settings, filter status, error codes, etc. Thanks to this, control is more convenient and visual.
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Hidden display. When switched off, the hidden info display blends in with the surface design of the indoor unit of the air conditioner and remains invisible. In active mode, the characters on the screen are visible through a certain place in the texture and all the necessary information is displayed on the display. On most models, the screen can be turned off using the remote control, and this feature can often be set to automatically hide after a certain period of inactivity, which will be useful at night.
Min. T for cooling mode
The lowest outdoor air temperature at which the air conditioner can operate normally in cooling mode.
The need for air cooling arises not only in hot weather — for example, efficient heat dissipation is constantly needed in closed rooms with a lot of heat-generating equipment (such as server rooms). And the limitation on the minimum outdoor temperature is because a large temperature difference between the condenser (heater) of the outdoor unit and the environment can damage the circuits.
Note that in domestic air conditioners, this limit can be quite high — +20 °С and even higher (up to +25 °С); however, additional cooling is usually required for warmer weather, and such air temperatures are not so high as to cause significant discomfort. But in professional units, the minimum temperature for the cooling mode can be significantly below zero — up to -40 °C and even lower.
It is also worth mentioning that in the presence of a heating mode, the permissible temperature for it is noticeably lower than for the cooling mode. It is due to the difference between the formats of the air conditioner in these modes.
