Air-water heat pump with solar thermal and fireplace? Cost/benefit/meaning

Nope. We have underfloor heating throughout the entire house (the basement is unheated for us, as it's a utility basement). In addition, there is a central ventilation system which is built into the same unit as the regular heating. The heat recovery is also integrated into that same unit. However, the systems themselves are separate from each other.
If you're only at 2000 kWh for heating with hot water, then you are really doing well. We are four people and like it warm (24-25 degrees in the living room). The central ventilation system does not have its own meter for us – the entire unit is connected to a separate meter.

OK – for us it is "only" between 21 and 23 degrees
But you are definitely assuming way too much consumption for the ventilation. You would need to find out how many watts the fan motors require.
Is the air in your heating system heated separately as well, or does it just run normally through the heat exchanger?

A completely different question:

Why don't you put a few photovoltaic modules on the roof instead of the domestic hot water heating (which I don't find suitable in this combination anyway) and generate your own electricity for the air-water heat pump (over the course of the year)?

That is, very likely, the better solution.

: That's nice, we also have the LWZ 403 SOL, but from the subsidiary company "Tecalor" standing in the basement...

A completely different question:

Why don’t you install a few photovoltaic modules on the roof instead of the domestic hot water heating (which I don’t find suitable in this combination anyway) and generate your own electricity for the air-to-water heat pump (viewed over the year)?

That is, with high probability, the better solution.

: That’s nice, we also have the LWZ 403 SOL, but from the subsidiary "Tecalor" installed in the basement...

In winter, when I need the electricity for the heat pump, no one comes from the roof. And hot water preparation in summer? Three quarters of an hour per day or max. 2 kWh...? We pay €110 per month in advance for heat pump and household electricity together. For that, photovoltaic doesn’t pay off with the low possible self-consumption without storage and the low feed-in tariff – especially if the system is financed. Solar, well, you’re right, let’s not even talk about that...

. For that, with the low possible self-consumption without storage and the low feed-in tariff, photovoltaics are not worthwhile either - especially if the system is financed. As for solar, you’re right, let’s not even talk about that...

Hm, I wouldn’t agree with that. My brother has been living in his house for two years and also has an air-to-water heat pump + photovoltaics on the roof. Over the course of the year, he gets more money from the grid operator than he has to pay for electricity purchases and the loan burden.

Well, he still has a higher feed-in tariff than we do, but even with our tariff, there would still be some left over.

We plan to install a battery storage in the technical room as soon as batteries become cheaper (and thus significantly more profitable than today) – at the latest then, the combination will definitely make sense.

Best regards,

Dirk

Even though I often agree with . Here, I agree from my own experience with . Especially when I see what we have produced/ fed in over the last few months, it only pays off to a limited extent.
We have a 5.5 kWp system on the house with almost perfect south orientation.
After self-consumption, we fed in only about 35 kW in December. Not because self-consumption was that high, but because production was so low. In January, we were at a "generous" 90 kW.
In contrast, our heat pump had a daily consumption of an average of 24 kWh. That means about 700 kWh in 30 days. Although I had not yet noted the data in December.
Theoretically, would be right. Why not still use the photovoltaic power anyway?
Reason:
As an operator of a heat pump, you can obtain the discounted heat pump electricity for this. The kWh is just under 0.20 euros. But if you operate the heat pump (partly) via the photovoltaic system, the purchase of the heat pump electricity is eliminated. Then the heat pump must be operated with regular electricity = about 0.25 euros/kWh.
Then the whole thing simply does not pay off, especially in winter:
700 kWh x 0.25 = 175 euros vs. 700 kWh x 0.20 euros = 140 euros Difference = 35 euros
Potential max. savings via photovoltaic in January: 90 kWh x 0.25 = 22.50 euros
Results in a loss of 12.50 euros for January.
Not yet considered here is the taxation of the self-consumed electricity mentioned in the other thread (photovoltaic system).
I cannot judge the summer months now. However, I suspect that we will not draw huge amounts of electricity for water heating.
We had actually also considered powering the heat pump via photovoltaics to optimize self-consumption. After several hints from electricians and solar experts—especially regarding the electricity purchase for the heat pump—we gave up on that idea.

Hm, I wouldn’t agree with that. My brother has been living in his house for two years and also has an air-to-water heat pump + photovoltaic system on the roof. Over the course of the year, he receives more money from the grid operator than he has to pay for electricity purchases & the loan burden.

Okay, he still has a higher feed-in tariff than we do, but even with our tariff there would still be something left over.

We plan to install one of those in the utility room as soon as battery storage becomes cheaper (and thus significantly more profitable than today) – by then at the latest, the combination definitely makes sense.

Regards,

Dirk

According to my research (last done in 2014), the legislator has almost halved solar power subsidies over the past two years. Those who install a system with a capacity of up to 10 kW in March 2014 receive only 13.41 cents per kWh of fed-in solar power. For systems installed in early 2012, one still received 24.43 cents per kWh. In addition, system prices are only declining slowly now.
It is only profitable if you have an extremely sunny location, get the system very cheaply, and have (in practice hardly possible without storage) a high self-consumption.

Even in 2012 (move-in), when I considered the idea, the return (with external financing, with reserves, insurance contributions) was in the low single-digit range. And with financing using equity, purely economically viewed over a period of 20 years, I would rather invest in blue chips.