Passive house, heating combination with solar, energy recovery, photovoltaics?

Solar energy is used for hot water in conjunction with a large buffer.

-that only works in the corresponding season, saving between 100 to 200 euros per year, no more.
Component activation is essential here.

What is recommended for additional sources?

-dv heat pump, but only a small one, since it is only an auxiliary heater.
-Pellets are too expensive and increasingly uneconomical, already more expensive than gas/oil this year again.

And I thought I’d put a few more photovoltaic panels on the roof to save even more and thus minimize the energy costs of the electrical devices and fan motors of the comfort ventilation, etc...

-that is not economical at all, since you currently get more for the kWh than you pay. It’s also not a good investment.
Covering the electricity for the heating register with photovoltaics is nothing but burning money.

A statement about the costs can only be made when the parameters are known. So size, equipment,...

Your father as construction manager is certainly good, since he will possibly be permanently on site. I would involve him right away.

But your father does not seem to me to be up to date with the latest technology, otherwise you probably wouldn’t have these questions.

Best regards

No, he is not the right person for passive houses, but he is generally very knowledgeable. Therefore, I will also involve an additional builder who specializes in passive houses; it will cost me a few euros, but he should be able to spot any defects during construction if any are made. Of course, before I pay any installment :D

Alright Parcus, what would be your solution regarding warm water in winter? And for additional heating? So photovoltaic on the roof and feeding into the grid to cover the supplementary heating of the comfort ventilation?

Why doesn’t it pay off if you feed your electricity into the grid, get your money for it, and finance the electricity used for, for example, heating via the heating register?

A fireplace is generally out of the question since the house has to be airtight. Pellet stoves are also becoming more expensive, not profitable.

What remains the best solution?

And heating additionally?

-a small DV heat pump, which achieves an annual performance factor of over 5.5

So photovoltaic on the roof and feeding it into the grid to cover the supplementary heating of the comfort ventilation?

-No, only for feeding in. The realistic return is 3%,
don't fall for the marketing strategists.
Apart from that, you will become a business owner,...

I see photovoltaic separate from the house as an investment for returns.

Yes, with photovoltaics you sell electricity at a price, which means you receive money per month/year for the electricity you feed into the grid...

Logically, the money I receive there is spent again on the electricity I consume in the house. This includes the motors of the fans, etc.

Or do I have some kind of misconception there?

What is a DV heat pump... I don't know that abbreviation?

Exactly, it is a net metering, meaning the feed-in is credited to you. It is therefore completely uneconomical to finance a photovoltaic system.

DV heat pump = direct evaporator, i.e., 2nd circuit, without electric pump

Yes, but how else is a photovoltaic system used? The money you make with it is spent again... Whether I treat myself to a vacation with it or pay my electricity bill with it is up to each individual. But it's better to cover your costs like (electricity etc.) with it. Or am I misunderstanding something? How does such a DV heat pump work?