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.
Modes and programs
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. Filters
Types of additional filters that are standard on the air conditioner (in addition to the simplest mechanical cleaning filters, which are found in all models).
We emphasize that we are talking specifically about the filters supplied in the kit; Some models allow you to separately purchase additional elements for air purification, but this possibility is not taken into account in this case. As for specific options, the most popular in modern air conditioners are
ionizers, various
antibacterial filters(including
catechin elements and
UV lamps), devices for
fine cleaning (including
HEPA filters),
antifungal,
antiallergenic,
deodorizing and
formaldehyde filters, and also elements that combine several functions at once (for example,
catalytic). Here is a detailed description of each of them:
— Ionizer. The action of the ionizer is based on the saturation of the air with negatively charged ions. They provide a feeling of fresh air, have a bactericidal effect, and are considered beneficial for overall health. One of the advanced types of ionizers are also
plasma (electrostatic)...filters. Along with the saturation of air masses with useful air ions, they are assigned the task of air purification. Such filters can quite effectively destroy harmful microorganisms, destroy some harmful substances, and trap grains of dust, smoke, soot, etc. — these particles, under the influence of ionized air, themselves acquire a charge and are attracted to the filter plates.
— Fine cleaning. This term usually refers to advanced mechanical filters that provide air filtration at a microscopic level. The specific effectiveness of such devices may vary; it should be clarified separately in each case. Note also that the HEPAs described below are also, in fact, fine filters; however, they use a specific operating principle and are inherently highly efficient. Therefore, the presence of HEPA filters is indicated separately.
— HEPA filter. A special type of mechanical fine filters. Thanks to the special design of the microchannels through which air passes in such a filter, such devices can trap particles much smaller in size than the size of the microchannels. For comparison, the effectiveness of a HEPA filter is assessed by its ability to capture contaminants measuring 0.1 - 0.3 microns (with such particles, such a filter is least effective), while the size of most bacteria starts at 0.5 microns. Based on their effectiveness, such filters are divided into classes; Nowadays, HEPA classes from 10 (retains at least 85% of the mentioned particles) to 14 (filtration efficiency reaches 99.995%) are relevant.
- Catechin. In fact, it is a type of antibacterial filters described below, created on the basis of catechins - natural organic substances with a powerful antioxidant effect. Such filters are highly effective in fighting bacteria and viruses, but they are not cheap; In light of these features, they are separated into a separate category.
- Catalytic. Most often, this term refers to photocatalytic, or “zeolite” filters - devices that operate using a special substance (photocatalyst) and UV radiation. Under the influence of such radiation, the catalyst decomposes the organic matter falling on it into simpler substances - usually water and carbon dioxide. This technology not only allows you to remove harmful impurities from the air (at the level of individual molecules), but also provides a good bactericidal and antiviral effect. Moreover, such a filter requires virtually no maintenance: the photocatalyst is not consumed during operation, and the reaction products freely evaporate outside. On the other hand, the price of such elements is quite high.
- Antibacterial. Various filters designed to destroy bacteria and other harmful organisms - viruses, fungi, etc. The specific operating principle, level of efficiency and maintenance rules for such filters may vary; these details should be clarified in the documentation for the air conditioner. However, if air disinfection is of fundamental importance to you, such a filter will definitely not be out of place. Let us note only two nuances in this regard. Firstly, catechol elements are usually not included in this category, although they have the same purpose (see above); secondly, not every antibacterial filter is capable of effectively fighting viruses - again, it would not hurt to clarify this point separately.
It is also worth considering that no matter how effective the air conditioner filters are, thorough air disinfection is not its main task; specialized devices should be used for these purposes.
- Antifungal. A specialized filter for removing harmful fungi from the air, such as mold. The antibacterial devices described above also have this function to one degree or another; however, this type of filter is much more effective in this regard. On the other hand, the need to intensively fight specifically fungi does not arise so often, and for other cases, the same antibacterial filters are usually quite sufficient. So antifungal elements are used quite rarely in modern air conditioners.
- Anti-allergenic. Filters designed primarily to remove allergy-causing contaminants from the air: pollen (including from indoor plants), dust mites, particles of pet hair, etc. The specific operating principle of such filters may vary and should be clarified separately. Thus, relatively inexpensive air conditioners usually use simple mechanical cleaning, and the term “anti-allergenic” is more of a marketing ploy than a real description of the filter’s specialization. More advanced models often include more advanced technologies - for example, an enzyme filter that breaks down allergens into simple, harmless substances like water and carbon dioxide.
- Ultraviolet lamp. A lamp that processes the air passing through the air conditioner with UV radiation. This treatment provides a bactericidal effect: ultraviolet light neutralizes most bacteria, viruses and fungi. True, in general the efficiency of such lamps is not particularly high; however, they are a great addition to an antibacterial filter. And even without such a filter, the quality of air purification of an air conditioner with a UV lamp will be higher than that of a similar model without such a lamp.
We would like to emphasize that this function should not be confused with the catalytic (photocatalytic) filter described above - UV lamps have a much simpler design and operating principle.
— Deodorizing (charcoal). A specialized filter designed, among other things, to combat unpleasant odors. Acts at the molecular level, allowing ordinary air to pass through and absorbing molecules of substances that create unpleasant odors; Of course, it is also capable of trapping larger particles, such as smoke. Activated carbon is most often used as a filter element - hence one of the variants of the name; There are filters based on other substances, but they also have similar properties. It is worth keeping in mind that in any deodorizing filter the working element must be changed periodically - when its resource is exhausted, it becomes useless and can even emit harmful substances itself.
- Formaldehyde. A specialized filter for removing formaldehyde and some other harmful organic compounds (for example, ammonia, benzene and/or hydrogen sulfide) from the air. The source of such substances can be both external pollution (for example, emissions from industrial enterprises) and some objects in the room itself: new furniture or curtains, some types of floor and wall coverings (immediately after application), spoiled food, cigarette smoke, etc. n. The specific operating principle of filters of this type may vary. Most often, the so-called cryocatalytic element is used, in which the catalyst decomposes organic matter into simpler, harmless components, and then restores its properties due to the cold when the air conditioner operates for cooling. In addition, many catalytic (photocatalytic) filters (see above) have similar capabilities, so one such element can be declared in the characteristics as two types of filters at once - both catalytic and formaldehyde.
In addition to the varieties described above, other types of filters may be found in modern air conditioners, in particular:
— Air purifying. A general name used for different types of filters. This term often denotes the simplest elements of coarse cleaning (for advertising purposes - so that the list of filters in the characteristics is larger). However, there is also another option - devices created on the basis of specific proprietary technologies and which do not fit into any of the varieties described above; such devices can combine several functions simultaneously (for example, fine filtration and antibacterial effect).
— Dust collecting. Most often we are talking about a simple mechanical filter that traps dust and other relatively large particles. Almost all modern air conditioners are equipped with such devices, but in some models the presence of “dust” filters is specified separately - mainly for advertising purposes.
— With vitamin C. A filter that saturates the air with vitamin C. It is believed that this supplement has a positive effect on immunity and skin condition; There is no clear evidence of this, but in conditions of vitamin deficiency, such a device will definitely not be superfluous.
- Preliminary. Mechanical coarse filter installed in front of the main set of filters. Detains relatively large contaminants, preventing them from reaching other filter elements and removing part of the “load” from them. At the same time, the design of the pre-filter is, as a rule, as simple as possible, and its maintenance is limited to periodic shaking or washing.
— “Ionic” (for example, Smart Ion, etc.). As a rule, it is the same electrostatic filter (see above), but presented under one or another brand name.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.
Heating capacity
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.Air flow
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.
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.