Operate heat pump autonomously with photovoltaic system.

Links are not allowed here anyway...

Links sind hier eh nicht erlaubt...

Then you will have to believe me. My photovoltaic system will cost: rounded up 15,000€, of which 5,000€ is a repayment grant. After 20 years, without the photovoltaic system, I will pay about 18,000€ in electricity costs assuming a constant electricity price of 0.27€. Which, of course, is unrealistic. I expect about 0.40€ in 20 years. Which would drive electricity costs even higher.

Tesla Powerwall 6.3 kWh + BenQ 21x 280W = 5.88 kWp

Attention unconfirmed half-knowledge: Don't current batteries have a half-life of 8-12 years?

Attention unconfirmed half-knowledge: Don’t current batteries have a half-life of 8-12 years?

5,000 - 10,000 charge cycles. So it depends on your consumption behavior. In addition, some manufacturers offer an extended warranty. And after 10 years, storage systems will surely only cost half as much and be twice as good. So it still pays off. The higher your current electricity costs, the more you should consider getting a system. But there are certainly experts who have a different opinion. It’s enough if I am convinced myself.

Would you like to say what is included in the interior finishing?

Finishing up to drywall and screed. Everything after that is done by yourself. That means: filling and sanding, laying the floor, tiling the bathroom, etc.

And what does this system cost monthly? How about taxes?

In the end, it won't be cheaper, but also not more expensive. (Without a storage unit) it's initially just a matter of shifting money from the right pocket to the left... And after 10-14 years we can talk about it being "worth it."

Why monthly? Do you mean the installment for the loan taken out for it?