Air conditioning in new construction - What preparations?

We only had one power cable installed in the bedroom. I hope that will be enough in case we ever want/need an air conditioner there.

Only if it is supposed to be a fan.

We have the same topic: preparation for refrigerant line, condensate drain, and separate power/control line for indoor unit/outdoor unit. Make sure you choose a brand and carry out the corresponding preparation - depending on the brand/model, there may be different preparations.

Because what is missing?

Everything that is written in the first post.

You can look at it however you want, as long as the houses are built/exposed to sunlight and not enclosed in the mountain/slope or in the forest by trees, then it will get warm and indeed more often than 2 weeks a year. You only have to look at the weather records of recent years/decades.

And due to the intended heat storage through modern construction methods, the warmth stays inside. Ventilating at night is rather wishful thinking. In the morning, the sun is there again and cheerfully heats up the houses for hours again. Shading and other compensatory measures have their limits.

Our outdoor unit is on the carport roof, a man carried it up there, I thought it can't be that heavy. We have 1 split unit for the entire upper floor, 1 for the office and 1 for living/dining/cooking. According to the consultant, it's enough if you cool down the upper floor in the evening; the houses are very tight nowadays.

It depends on the size of the entire system and also on the number of indoor units. The weight can be between 30-40 kg up to easily 200 kg. It strongly depends on how the system is set up. I have carried several 3.5 kW systems alone onto the roof of a three-story building. But they were only about 50 kg each.

On the other hand, I left the 4x multisplit units nicely standing on the ground.

The fact is you need a concept and have to decide on a manufacturer and well, if you want to pre-install, then have the parts laid in advance, which have already been described at the beginning.

I did not mention that the device is supposed to hang on an exterior wall in our case. Power is already there because it is difficult to retrofit. The cables then only have to go through the wall once. If that weren’t possible, an air conditioner could never be retrofitted, right? If the indoor unit is supposed to hang in the middle of the house or serve several rooms, of course you have to plan more accordingly.

Sure, if you are only planning one device and there is space directly on the outside of the bedroom wall etc., then you only need one core drilling later.

But often, for example, a wall-mounted unit or one on the roof is not an option, and homeowners want the device as hidden as possible, then you have to think and plan ahead.