The choice of an air conditioner is carried out according to several criteria, the main of which is power. Overestimation will lead to unnecessary consumption of electricity, and underestimation will lead to insufficient efficient operation of the unit. Therefore, before buying it, you need to make an approximate calculation of the power.
Formula calculation
There is a basic value used to quickly find the required capacity of the air conditioner: 1 kW per 10 square meters of room. That is, to heat or cool a room of 25 square meters, you should buy a 2.5 kW unit. However, this does not take into account other factors affecting the calculated value. And first of all, it is the height of the ceilings.
A more accurate formula looks like Q = S * h * q, where S is the area of the space to be taken into account, h is the height of the walls, q is the applied coefficient, and Q is the final result, calculated in kilowatts. The q coefficient depends on the illumination of the room, as well as on the degree of heat loss to the surrounding atmosphere, depending on the location of the air conditioner: in the corner or in the center of the building. The standard number is 35 watts per cubic meter, while it rises by 5 watts / cubic meter for sunny rooms and decreases by the same figure for shaded ones. This formula is applicable only for housing and other domestic premises, it is not used to calculate the capacity of air conditioners installed in kiosks and other similar facilities.
As an example, we can take a standard room with an area of 20 square meters and a ceiling height of 2.5 m. Q = 20 * 2.5 * 0.035 = 1.75 kW. This formula is more convenient than the first calculation in that it takes into account the height of the ceiling, since it can vary from 2 to 4 m, and if the official hall is to be heated, then the final value will be higher.
Accounting for errors
To get a more accurate result, several other constants should be substituted into the formula. Firstly, this is the heat loss of people living in the room. In a normal state, one person requires 0.1 kW, engaged in physical activity (for gyms) - 0.2. That is, if 3 people sleep in the room or are engaged in normal activities, then 0.3 kW is added to the result.
Secondly, you should compensate for the heat generated by household appliances: a computer, electric or gas stove, oven, TV. If there is 0.3 kW added to the computer, a stove or oven - the same amount. For a TV, it is enough to add 0.2 kW. Thus, in the presence of the first and last in the living room, an additional 0.5 kW is included in the formula.
The number of windows in a given room should also be taken into account. If the glazing area exceeds 2 square meters, then for each subsequent one, 0.15 kW is added. This figure can be higher or lower, depending on the degree of illumination: in winter the sun heats up the room, and the power of the air conditioner can be reduced, in summer, insolation becomes a minus, and the parameter must be increased.
