Estimate the legal obligation for remediation

You are dealing with the topic of old buildings or houses that were not built according to the [Energieeinsparverordnung]. A house built in 2000 was constructed according to the [Energieeinsparverordnung], so you can disregard the issue of forced renovations.

If you want to insulate facades, they must be insulated according to the [Energieeinsparverordnung], but only then.

Brief regards