Old gas heater defective -> need a new one, but which one?!?

Photovoltaic system can't fit anymore? But I read something different in various forums (but you shouldn't use a storage)

I once read about acquisition costs of 1300-1400€ (net) per kWP = 10 kWP x 1350 euros = 13,500 euros net = approx. 16,000 euros gross

"Example: A 5-kWP roof system at a suitable location in central Germany produces an average of 910 kWh per kWp of installed capacity annually. This results in an average annual yield of 5 x 910 kWh = 4,550 kWh."

Thus 10 kWP system = 9,100 kWh * 9.87 cents/kWh = approx. 900 euros annually

16,000€ / 900€ = 17.7 years (without maintenance / repair etc.)

The invoice is wrong because 1300-1400€ net is way too expensive, calculate rather 1100€ And you divide the (overpriced) gross system price by the net feed-in tariff. Generally, forget gross prices.

I once read about acquisition costs of 1300-1400€ (net) per kWP = 10 kWP x 1350 Euro = 13,500 Euro net = approx. 16,000 Euro gross

"Example: A 5-kWP roof system at a suitable location in the central German region produces an average of 910 kWh per kWp of installed capacity annually. This results in an average annual yield of 5 x 910 kWh = 4,550 kWh."

Thus, a 10 kWP system = 9,100 kWh * 9.87 cents/kWh = approx. 900 Euro annually

16,000€ / 900€ = 17.7 years (without maintenance / repair etc.)

I already have a few offers here. They are about ~1115€ / kWP (net)

What kind of heat pump is supposed to be installed to cost €26,000? Or is it a brine heat pump including drilling, etc?

In the existing building, you also receive additional funding for the underfloor heating and pipes. That fits well.

What kind of heat pump is supposed to be installed that it should cost 26,000€? Or is it a brine heat pump including drilling, etc?

That will be with the switch to central hot water.