Experiences with heat pumps and photovoltaics?

Exactly that needs to be clarified, whether this is an option. Whether a ground drilling is possible and how much a ground drilling costs... for loops your property is probably a bit too small. The problem with the combination of air-water heat pump and photovoltaic is that the photovoltaic system almost only delivers electricity in spring, summer, and autumn, and those are not exactly the months when your air-water heat pump needs a lot of electricity. You still have to do the math to see if there is still an attractive feed-in tariff in your area. Here in [dtld], the whole thing only makes sense if you consume as much electricity as possible yourself. Also, the maintenance costs of a photovoltaic system should not be underestimated. After a certain time, the inverters have to be replaced, and during the entire runtime, the system must not break down, otherwise the already optimized calculation is ruined. But no energy consultant will tell you that.

Nonsense. If that were true, the annual performance factor would be well below 2. I've never heard or read of anyone with such a poor value.

Math just isn't for everyone....

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Geothermal energy won't pay off for a new building even in 100 years. You can do it if there is no space for an air-to-water heat pump or out of conviction.

Also consider your consumption times and the sunlight hours of your region

Moreover, the maintenance costs of a photovoltaic system should not be underestimated. After a certain period, the inverter has to be replaced, and during the entire operational lifetime, the system must not break down, otherwise the already optimistic calculation is ruined.

Not to forget the regular cleaning of the modules to maintain maximum performance. In the summer months, it is not noticeable, but in autumn/spring, with possibly unfavorable angles of incidence, any contamination (bird droppings, insect droppings, sticky plant seeds, moss spores, etc.) reduces the efficiency enormously. You know yourself how windows/skylights look after half a year without cleaning...

I would just clarify for myself what is most feasible and also makes sense – so, to start with, discuss the variants of the heat pump for myself. You can also take a closer look at the following points and consider: Air or water heat pump: Relatively easy to install, can be used for the heating renovation of old buildings, but is also suitable for all well-insulated (!) buildings without or with a small garden. It can be ideally combined with surface heating in the floor or wall, and is space-saving for indoor or outdoor installation. Ground heat pump: Usually can be used as the sole heating system. Suitable for old and new buildings with a large, treeless plot, as roots can cause problems otherwise. But: A ground collector requires two to three times as much horizontal outdoor space as the heated floor area. Vertically installed ground probes also need a lot of land area. You have to be aware of that. Groundwater: can also be used as the sole heating system. Suitable for buildings outside a water protection area with a very large garden and requires two elaborate drillings for one production and one injection well each. Surely it can also be combined with a photovoltaic system and that makes sense; I have seen it myself at my parents’, and they are very satisfied.

Even vertical ground probes installed deep underground require a lot of land area. One must be aware of that.

why is that?