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.
Functions
Additional features provided by the device.
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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).
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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.
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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.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.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.
Maximum height difference between units
The maximum height difference allowed for split system units. For multi splits (see "Type"), in this case, we mean the difference in height between the highest and lowest unit.
When installing units at different heights, a pressure difference arises in the system — the greater the height difference, the greater this difference, and if it is too large, the system will not be able to work normally.
Indoor unit dimensions (WxHxD)
Dimensions of the indoor unit of the air conditioner in height, width and depth.
These dimensions allow you to estimate how much space you need to place the device. In this case, of particular importance — mainly for split and multi split systems with wall mounting is the width of the indoor unit. The fact is that in terms of the height and depth of the internal blocks, most of these systems differ slightly in general but the differences in width are much more noticeable. So, the narrowest models have a width of
76 – 80 cm or
less, and the largest ones occupy
91 – 95 cm, and often
more. At the same time, the more powerful the air conditioner, the wider it is, usually, but there is no rigid dependence here.