Before purchasing, one should calmly review:
- Construction and performance description
- Design documents for the heating system, if available (heating load calculation, [Energieeinsparverordnung]-certificate, protocol of the hydraulic balancing)
- Consumption data/bills from recent years specifying what/how/where (is there a separate electricity meter for the heat pump?)
The real estate agent should provide the documents. No accompanying nonsense.
- If the paperwork is acceptable, one should inspect the house with an expert (surveyor, someone knowledgeable).
- If everything is then in order and the house is liked, one can buy. A certain buffer should be planned anyway.