Is an air conditioner necessary in a south-facing location?

Photos would be great!

I will deliver it when everything is finished! Or rather, a few first pictures. One shows the access to the chimney duct used for distribution, then the bedroom/including a picture of the access from the attic (here it wasn't possible without a condensate pump) and the other picture shows the children's room (95% of the cable duct disappears behind the wardrobe):

Unfortunately, I can’t edit any more, so they really work very neatly and limit the "damage" or openings to a minimum. I’m really curious about the outdoor unit; it’s supposed to go on the roof today. Through the skylight and then onto a bracket. In the living room, it looks comparable to the kids’ room, so we’ll have to come up with something to possibly make the cable duct "disappear." We could have also placed the indoor unit directly on the chimney flues there, but that would have been worse for air distribution, and for me, function simply comes first. Still, you can get creative and possibly make it disappear with an eye-catcher; we’ll see, but for now, the right idea is still missing. It runs at about 2.50m there, so a cabinet is out of the question. It’s just an old building from 1900, but has been owned by my wife’s family ever since!

Short update:

Indoor units are finished, condensate pump in the basement as well. Yesterday it was not possible to go on the roof due to the weather, so now there are two options. The first would be to complete the remaining installation and commissioning today (the master/boss has to do this himself) on Monday, as he has an appointment today. Or finish everything on Monday; we agreed on this plan.

Work is still very clean and it came directly from him that we will of course not be charged for the replacement of the cable ducts. He had tried with 7x7cm cable ducts, but that did not fit with the supply and return lines, control cables, condensate and power cables. But the additional effort will also not be charged, which of course should be clear, but it is still nice that he states it himself directly.

So the outdoor unit is installed and the system is running, only the condensate drain still needs to be done. There was a small "problem," a part was missing due to a misunderstanding. But it will be done soon, and then the commissioning including introduction will take place. They had to carry a lot on the roof, but everything looks clean:

Unfortunately, there was a small "accident," they really worked very cleanly, neatly, and carefully without breaking anything. And then the drill bit broke off while drilling a hole in the support brackets and took the path over the roof towards the terrace roof:



But the trainee immediately came to report it and to check with me, it will be reported to the insurance and will be taken care of. So everything is okay!

Also, regarding the somewhat longer duration, which can occur in old buildings and with careful working methods, it was immediately said that a consensus would certainly be sought. So we are satisfied and the first short tests were promising, the first indoor unit can already be controlled via smartphone. The rest I still have to integrate or check again that it connects to the home Wi-Fi via WPS.

So, here’s some feedback again, since the first hot days were coming and are still coming. The system is running great, even with outside temperatures of 30 degrees or the outdoor unit already reporting 37 degrees, you can easily maintain 20 degrees indoors without running at full capacity, or even 18 degrees if you want. On the hottest day so far, we directly tested how it works for the ground floor, leaving the doors open, and as expected, the ground floor also benefits significantly. The indoor units mostly run in automatic mode and feel like they do not go higher than level 2 or 3 out of 5 (plus there is also the power function).

In the indoor unit’s quiet mode for night, you can barely hear it, so we let it turn on again at a certain time at night (in the bedroom). We are still super happy with the system, it was the right decision. A maintenance contract will also be made, and to make it easier, we are including the heating in it.

The only small "drawback," which is just a testing matter, is that the app and the setting via remote control sometimes interfere with each other. I still have to figure out exactly what causes this. Sometimes the app’s timer doesn’t work, but that seems to be because the device is not properly turned off using the remote control. So this is just a matter of getting used to it.
Oh, and we need to take another look at the condensate pump in the bedroom, it makes some noise. Potentially, I think these are "vibrations" that get amplified through the cable duct. We’ll see!