Heating type for new construction - Which is the best?

I have decided on an KFW 55 for an air-to-water heat pump with underfloor heating.

We wanted to have a geothermal heat pump and today we found out that the installer saw on the geological maps that you would have to drill more than 100 meters deep (if that is even allowed) and that would be way too expensive.

He now recommends a Waterkotte AI 1 Eco Touch air heat pump with 18kW. You need an outdoor unit for the wall, which I find more than disturbing from an aesthetic point of view. Terrible!

The alternative is a Viessmann gas boiler with solar or photovoltaic support. However, according to the general contractor, this is the significantly more expensive solution in terms of acquisition costs. But just to avoid that ugly outdoor unit, it is already worth a few euros to us.

I just took a quick look... but as I see it, this Waterkotte is not even an air-water heat pump.

What do you think about it?

The installer has a screw loose.

First of all, of course deeper than 100m. Less than 100m total depth means heating loads under 5-6kw, which is rather unlikely for such a large house.
The great 100m limit can be handled with an additional application, no problem at all. Of course, there are always exclusion reasons, but is there really any indication for that?

And apart from that, an 18kw heat pump, is he crazy?! Does he want to heat an apartment building?!
Throw the installer out. He only knows gas and has no idea about heat pumps.

This is a general contractor installer. I cannot fire him. But I can possibly use factual arguments to work towards a different solution.

Do you know where one can see these geology maps that indicate whether a geothermal heat pump makes sense or not?

Not that I misunderstood him about the drilling depth and it was more than 150 meters. It was also the general contractor who told me that, not the installer. But I can call him too.

PS: Request a heating load calculation, room by room. He should prove the 18kw (if he wants to drill for 18kw it’s clear that it will be expensive ...). Don’t forget, geothermal energy 5000€ subsidy from BAFA (almost completely pays for the drilling).

Exactly, with us too,