This is what it looks like! A lot depends on how many units need to be supplied and how much power is required. Then there's the question of the length of the lines, since the coolant line is not exactly cheap.
Then there are factors like installation location, brand, and equipment. We were now in the five-figure range for 4 indoor units and the corresponding outdoor unit. But the outdoor unit alone is already a major cost factor.
But I can already say that it is worth it. The gain in living quality during the warm to hot times of the year is simply huge. We have the bedrooms under the roof; previously you would have been lying there sweating in bed. The air conditioning now provides a very pleasant sleeping climate. In addition, it can also be used as heating during the transitional phase, as it is apparently more effective there than the central heating.