Away from fossil fuels - House from 1999

It can be roughly derived. 1000l/a of oil equals 10,000kWh. Heat pump with radiator heating has a COP between 2.5 and 3 or even worse, so 3,300 to 4,000 kWh/a. At 30 ct/kWh about 1000€/a. The COP depends on the supply temperature and from a COP of 3 it is worthwhile.

They have a special heat pump tariff and as far as I know they only pay 22ct / kWh for heating electricity.

So, as you can see, there are many aspects to consider, then there are things that we cannot quantify at the present time, such as the development of the oil price and the creation of future funding programs. If I find a good energy consultant, I will review the project, otherwise I will probably wait. There are also completely different aspects related to my parents, which I do not want to elaborate on here...

Matthias