Installation and type of temperature control - What is it called?

On the topic of heating: financially, replacing the gas heating system will not be worthwhile. As long as it is running, leave it in place. A ventilation system is initially not affected by this.

An air conditioning system can be installed. Why not. However, the desire for it might quickly shrink once the roof is insulated. So I would approach it in that order.

Air-to-air heat pumps often do not pay off even in new buildings – so that certainly won’t be the case for you. The only one who will tell you otherwise is the salesperson from the heat pump company.

Simply replacing the radiators is also not always possible, as the flow rates and required supply temperatures will be different. So this should also be checked by a professional before you buy new radiators at the hardware store.

Otherwise: good luck with the project and hopefully a smooth resolution of the inheritance case.

We were able to clarify with our heating installers recently that the deliverer with the radiators "just replacing" is basically possible. We only need to install connectors because the old radiators have a 50cm distance and the new ones 45cm distance for the pipes. :-) We could also take radiators with a 50cm distance, but the additional costs are not proportional and the company is basically just profiting from it.

As for the air conditioning, we would at least have the advantage that we know a professional friend. So we could possibly install it ourselves with his help.

My husband is very sensitive to heat. I have had to accept those terrible fans in the bedroom for years. I hate being blown on so much...