Install air conditioning pipes under plaster?

I am a bit confused about our new building regarding air conditioning. I have contacted 3 companies so far, and they all said it will only be surface-mounted and I should get in touch once the plastering is done so they can take a look. There needs to be electricity outside at the outdoor unit, but nothing needs to be prepared inside.

However, I have seen insulated pipes embedded in the wall and also flush-mounted boxes for the indoor unit. Does anyone have experience with that? Is it really a problem because of condensation and maintenance?

And indeed, I received the statement from 3 companies now contacted that it will only be installed surface-mounted

Lines, even for an air conditioning system, can of course be installed flush without any problems. I have even seen systems where the lines ran on the raw concrete ceiling beneath the floor structure.

Now I have definitely seen that there are insulated pipes under plaster and also flush-mounted boxes for the indoor unit. Does anyone have experience with that? Is it still a problem because of condensation and maintainability?

Pipes can of course be laid under plaster without any problems even with an air conditioning system. I've even seen systems where the pipes ran on the raw concrete ceiling under the floor structure.

I did it like this. Flush-mounted box in the wall on the ground floor. Insulated copper pipes were routed upwards in the wall and laid on the raw ground floor ceiling. They now lie like normal water pipes in the insulation under the screed. Next to them is a protective conduit for the cable between the outdoor and indoor unit. Power is connected at the outdoor unit and passed on to the indoor unit via the connecting line.

The condensate hose in my case is routed downwards in the wall and led through the basement ceiling into the existing pump sump.

The bracket for the indoor unit is then mounted in front of the flush-mounted box so that it is no longer visible and all the connections disappear inside it.