Insulating a sand-lime brick wall / upgrading construction energetically

Energy Saving Ordinance § 10 Retrofitting in Installations and Buildings

For residential buildings with no more than two apartments, of which the owner has occupied one apartment themselves as of February 1, 2002, the obligations under paragraphs 1 to 3 are only to be fulfilled by the new owner in the event of a change of ownership after February 1, 2002. The deadline for fulfilling the obligation is two years from the first transfer of ownership.

And then, depending on the renovation components (e.g., new windows), these must also comply with the current Energy Saving Ordinance.

Or, for example, if you renovate the roof....

Mhh so the owner has never lived in the property.... but that is also a sentence you have to read 10 times. Now I don’t know how that affects things The roof is new we even still have remaining warranty on it and the windows were reglazed (so only new glass panes, the frames were retained) I generally think that’s it for now?! (I hope so) so we have not received any requirements from any side