Does it make sense to install an air conditioner?

No, all are honestly acquired. Partly for tests, etc. the 9kW system is now doing its service in my company.

The pipes are always simply copper tubes just with different diameters. So, the devices can generally be exchanged with each other or with minimal adjustments everything is possible. Nevertheless, of course, there are some things to consider and one should not approach it without expertise and a certificate of competence.

Yes, I installed the systems myself.

We don't have air conditioning, but windows with roller shutters. They stay down during the day when it is as warm as it is now. But sleeping in the south (the western rooms will also be affected) becomes a torture. I am now first thinking about a ceiling fan. In this respect: upgrade your bedrooms. In living areas or kitchen, I do not find it necessary.

Next week there will be days with over 40 degrees... I urgently need an air conditioner....

Many thanks to everyone. There were very many good suggestions. We would not install an air conditioner for now. If necessary, it can be done later when the need really arises. Wishing everyone a nice rest of the weekend!

One more note: It is best not to plan the bedroom facing south, that also brings quite a bit!

We have the northeast side on purpose, that is really very comfortable...

Full agreement. We have built in air conditioning directly and are very happy about it every day Power consumption in the hot summer of 2018...ridiculous 700 kWh (on hot days/weeks it runs 24/7)

If you have photovoltaics, all is well, but without it you move further and further away from low energy etc... Building a KfW 40 house, insulation power 10 so that nothing is lost in winter, and then blowing out energy in summer with the air conditioning, I think that doesn't fit together