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

Feed-in price August 2014: 0.1275 euros as a small addition

I just realized: In the calculation made above, I would have to take into account the "lost" feed-in revenue in case of using the photovoltaic electricity for the heat pump, which would further widen the return gap.

By now, this is the 1001st post on the topic of air-to-water heat pumps and water-bearing wood stoves. Unfortunately, I have not reached any conclusion! Not even the heating engineers can give a precise statement on whether it really makes sense and how complex the control system is, so that I do not destroy the efficiency of the air-to-water heat pump when the stove is not burning??

My collected facts are (feel free to correct me)
- If I plan a wood stove with water circuit, I need a buffer storage tank.
- An air-to-water heat pump does not need this buffer storage tank because it operates the underfloor heating directly, and it would be a waste of energy to heat the buffer of about 500 liters.
- If I take a scheme where solar is coupled with an air-to-water heat pump, I still end up with a buffer storage tank! How does that work in winter??? Do I take the surplus energy saved in summer and waste it in winter.
Solar and air-to-water heat pump is the biggest rubbish to me; in summer, when the air-to-water heat pump works efficiently, I support it, and in winter I have no help.

Which system/manufacturer covers everything? The complete control system from one manufacturer??? And as efficient as Vaillant geoTHERM

Without the stove, there is only one choice for me, and that is the Vaillant geoTHERM Plus

We are building with solid 36.5 Poroton without air atomizer (that is, for me, the invention of the century, I would never bring something like that into the house, I have two healthy hands to open the windows, but that is another topic)

160sqm on 2 floors

Good morning everyone,

Regarding your calculation, one really has to ask what actually pays off in the end. I got the information from an acquaintance that when he was building his house at that time, he had a combination of a photovoltaic system with east/west orientation and an air-to-water heat pump calculated, and this variant was more efficient than a purely south-facing photovoltaic system. Furthermore, he was left open to possibly installing a small number of south-oriented photovoltaic panels due to the garage orientation.

Until now, I actually also thought that an east/west orientation of the photovoltaic system combined with an air-to-water heat pump was the best combination. Especially considering, as you already mentioned, that in about 5-10 years batteries should be economical and profitable.

I recently attended a lecture where stoves with heat storage were discussed. It was pointed out that the combination of a photovoltaic system and such a stove was probably the best. What I also read is that a photovoltaic system in combination with an air-to-water heat pump is one variant. In this, the excess electricity generated by the photovoltaic system is used via a water storage tank for domestic hot water (so not underfloor heating, which is supplied by the air-to-water heat pump) in combination with an electric heating element. Of course, they say that the electricity is actually too valuable for this, but the 12 cents feed-in tariff does not make one rich either. I can’t say exactly about this either—it was just an idea or a contribution I had read somewhere.

Regarding the solid construction, do you mean with the air atomizer a ventilation system? At first, I also thought that you could easily ventilate, but with solid construction or something approaching KfW70 / 55 and beyond, I would meanwhile tend to a central or decentralized ventilation system. When you see that both persons are, for example, employed, in my opinion, the ventilation processes could not be maintained. If there is mold later somewhere, you‘ll only be annoyed. But that’s my point of view.

@hauslebau3r....

Thank you for your contribution... I am now coming to the same conclusion as you about photovoltaics... Does it all run automatically? So as soon as enough energy comes from the roof, do I use it myself? If not, do I have to buy? Then I would have to heat everything up nicely during the day, and then a buffer storage could even be an option again.

Oh man, it's not that simple..

So regarding the ventilation system, I agree with you, but we have two small children and there will always be life in the house. If no one is home, then it's something to think about. Still, I view the matter critically because if you have such a system, you really have to pay attention to maintenance and not just change a "little filter" occasionally. But that is not the topic now.

Therefore, I am building without additional insulation and with the Poroton brick I think we are doing quite well...

I don't think the children have the leisure to keep walking through the house to air it out...central systems are by the way relatively easy to maintain even for laypeople...provided you do it regularly...

It's about life in the house. My children are not home alone... I still have a wife, but that's not the topic... This is the keyword "regelmäßig" that 70% of ventilation system owners will not do and then it will quickly stop being fun when the dirt spreads in the apartment.