Replace gas with heat pump

I do not want to fundamentally disagree with you, but driving bans for older diesel cars prove that there is not always a grandfather clause. Furthermore, the following applies:

Currently, according to the Energy Saving Ordinance 2009, the requirement (§ 10) is that owners of buildings "heating boilers that are fed with liquid or gaseous fuels and were installed or set up before October 1, 1978 are no longer allowed to operate."

Whether or how this is controlled and what happens in case of violations, of course, I do not know.

Whether or how

That's relatively simple. The chimney sweep has to come regularly and will make sure of that.

The Energy Saving Ordinance with all its fuss can go to hell... a heating system runs, and as long as it runs, nobody has to fiddle with it. If it acts up, I call the technician

My remark was not only about stupid regulations. But if you want to claim warranty, it must also have been "serviced" according to the manufacturer's specifications.

It is that from 2030 no new ones are allowed to be put into operation. But not that none are allowed to be operated anymore. Small but fine difference