Heat pump consumption 2019 on a monthly basis

[...] approx. 30 years payback period compared to air-water heat pump [...] Therefore, brine remains something for enthusiasts [...]

I cannot leave it like that

Offers for devices from the heating installer with us were:

[*]Air-water heat pump approx. €9000 incl. installation
[*]Brine-water heat pump approx. €12000 incl. installation

Development of geothermal energy by own effort approx. €3000 total
BAFA grant €4500

In the end, there remains a difference of €1500
We will recover that in a few years and additionally do "something" good for the environment.

Did you determine the annual performance factor?
How was the heat source determined for the modulating heat pump and did it cause trouble with the parties involved?
Size of the hot water storage tank?

Wow, those are values, my wallet is getting jealous.

1. Have you determined the annual performance factor?
2. How was the heat source determined for the modulating heat pump, and did it cause any problems with the parties involved?
3. Size of the hot water storage tank?

1. Yes, but due to the proportionally higher hot water preparation compared to less insulated houses, the annual performance factor is just under 5 (currently 4.86).

2. The source was designed based on the heating load determined before construction (approx. 6-7 kW). The source could have been somewhat larger afterwards. Currently, the brine inlet and outlet temperatures are 4.2°C / -0.4°C.

3. 190 liters and otherwise no buffer (with good photovoltaic feed-in, 1-2 K more is "buffered" into the screed and slightly overheated).

Oh, I thought [Bohrung]! Well then, fine thing