Geothermal energy or air heat, experiences?

There is no one good site. A good point of contact is the pink forum.

Why we chose geothermal energy:

1) Through self-construction (trench collector), geothermal energy was cheaper than an air-to-water heat pump (subsidy of 5500€ with manufacturing costs of the collector at about 3000€)
2) Our main reason: We find the appearance of air-to-water heat pump outdoor units terrible, it was a no-go to have something like that standing around.
3) Nice add-on: Passive cooling is possible. After 2 summers I have to say: really better than expected. Of course not like an air conditioner, but almost free in operation and it successfully keeps the temperature down and the house stays under 23 degrees.

In principle, when the prerequisites are met, I prefer a trench collector with a brine heat pump over an air-water heat pump. When the prerequisites are met means for me: I myself have the leisure, the time, and the opportunity to get excavators and the like cheaply, and the property offers enough space for the collector area.

Air heat pumps are easier for the classic heating installer, who previously installed oil and gas systems, to sell. The problem here is that many heating installers use the planning service of the manufacturers, i.e., Company XL designs a heat pump for them, plans a safety buffer tank of 100 liters to compensate for botched hydraulics, and lets the underfloor heating be designed by the system manufacturer with standard temperatures as from 10 years ago, that is, flow 35°C and return 28°C.

For sizing the heat pump, a rough heating load is then calculated, like 100 m² x 35W/m plus safety margin plus surcharge for domestic hot water plus surcharge for blackout periods from the electricity supplier (because only one complains if his backside isn’t warm enough), and then it’s screwed up.

However, if you have a heating installer at hand who deals with the topic of heating load and the design of underfloor heating themselves and does not demonize the heat pump topic as some newfangled Sodom and Gomorrah, then an air heat pump can also be efficient and represent a reasonable price-performance ratio. Keyword: Panasonic Geisha and Co.