What do I need to consider when buying? How do I calculate the required cooling capacity?


The following points must be well considered:

  • Room size (length x width x height) - Calculate the room size in cubic metres (m³).
  • Location of the room - Rooms in the attic, rooms with high ceilings or rooms that are exposed to strong sunlight need a stronger output. When used in offices, equipment such as computers and printers may need to be included as they also give off heat. The number of people in the room must also be considered, as each person emits an average of 80 watts of heat.
  • Capacity- Generally, an air conditioner requires about 20-25 BTU per square metre of living space. BTU/h is the cooling capacity per hour. For example, 1000 BTU/h is equivalent to 293 watts per hour. 
    • How do I calculate the required cooling capacity?
      You can determine the watts and BTU required for an air conditioner by calculating 40 watts of power per cubic metre of volume as a general rule of thumb.

      An additional cooling capacity of approx. 100 watts per person is calculated. Therefore, it is better not to calculate too tightly.

    • Calculation example 20m² room:
      Assuming a room height of 2.5m: 20m² x 2.5m = 50m³.
      Required power:
      50m³ x 40 W = 2000 W
      2000 W / 293 = 6.8 * 1000 = 6825.9 BTU/h
      -> Thus a unit with 8000 BTU/h would be sufficient here.

  • Energy efficiencyUnits of energy efficiency class A or higher are to be preferred because of their low power consumption. Depending on the type, units of class A consume 11-15% less energy than a unit of class C, for example.

  • Installation - With monobloc air conditioners, you don't need any installation, you just need a socket for the power connection and an opening for the heat to escape (e.g. window). 

    Split air conditioners, on the other hand, consist of two units that are connected to each other by a pipe. The two units are one unit outdoors and one unit indoors. The compressor of a split air conditioner is located outside. This is also where the waste heat and operating noise is generated.

  • Price - The prices of mobile monobloc air conditioners depend not only on their performance and size, but also on the range of features, the available functions such as timer and sleep mode, and the design. Good, mobile monobloc air conditioners can already be bought relatively cheaply.

More information on the topic:

Still not sure which unit is enough for your needs? No problem! Our consultants will be glad to help you make the right choice: contact ecofort.