A multisplit is an outdoor unit that can be connected to several indoor units, which can be indistinctly wall, floor, ceiling, ductable and cassette. The multisplit units, each with its own effective yield and maximum connectable power, are classified according to the number of attacks in:

  • dualsplit (2 connections or ports);
  • trialsplit (3 attacks or ports);
  • quadrisplit (4 attacks or doors);
  • pentasplit (5 attacks or doors);
  • esasplit (6 attacks or doors).

But how do you determine which multi-split is best suited to air-conditioning an apartment or an office?

First of all it is necessary to establish the number of rooms to be air-conditioned, to calculate the kilowatts (kW) needed for each of them (see thermal sizing) and, finally, to group the same rooms by presumable contemporaneity of use of the splits (for example living area and sleeping area).

Consider for example that you want to air-condition 3 rooms of an apartment. Since these are 2 bedrooms and a living room, we will have that 2 of the 3 indoor units will generally be used simultaneously. The kilowatts required to air-condition these rooms are: 3.5 kW (living area), 2.5 kW and 2.5 kW (sleeping area). At this point, considering the contemporaneity of use, the powers of the indoor units must be added: thus we will have 3.5 kW for the living area and 5.0 kW (2.5 + 2.5) for the sleeping area.

Thanks to these data, a 5.4 kW trialsplit will be required with a maximum connectable power of 10.0 kW: in fact, both the maximum power of use (5.0 kW) and the total power of the indoor units (8.5 kW ) are compatible with the values ​​of the outdoor unit.


Instead, we analyze a case in which the rooms to be air-conditioned are occupied during the same hours of the day, as in the case of an office.

We consider, in fact, that we want to air-condition 3 rooms in an office, each of which requires 2.2 kW for air conditioning. In this case it is necessary to respect the yield value considering that the total sum of the powers of the 3 splits is 6.6 kW (2.2 + 2.2 + 2.2).

Because of these data, therefore, a 6.8 kW trialsplit will be required with a maximum connectable power of 12.0 kW: the 6.8 kW output will guarantee, in fact, a use of the internal units equal to 100%, also in case of simultaneous use of the 3 splits.


WARNING: it is essential that the sum of the kilowatts of all the indoor units never exceeds the value of the maximum connectable power of the multisplit, as it is essential that the total power of the indoor units, which are used simultaneously, must never exceed the value of the yeld.