Brine water / Air water - Specifications for the construction area

Good morning, I am new here in the forum and am trying to work my way through the topics here as best as possible. My family and I would like to build a single-family house - 150 sqm., NRW, new development area, total 3 people (2 adults 1 child) The development area "requires" a cold local heating system - meaning you pay a fixed price whether you use it all or not. However, there would then be a brine-water heating system included, including maintenance, etc. But on the other hand, you are tied to the supplier regarding the heat price - the system may not be powered by a photovoltaic system. Estimated monthly costs by the supplier are EUR 115,-- / monthly for heating (including cooling). What is your opinion on this? Do you accept the offer, or do you then take an air-water heat pump from the house manufacturer, as they say: "our system costs 60 EUR monthly." I am very skeptical, but I do not have the necessary expertise to assess this. Looking forward to your feedback

A standalone brine-water heat pump will easily cost you at least €13,000, more likely €20,000, including installation and drilling, plus maintenance is also required here. Divide the "saved" €60 difference over the estimated lifespan of the brine-water heat pump and decide :p

I assume the offered cold heat supply requires no further investment? That means the brine-water heat pump is included in the €120?

I'm not a fan of prescribed or imposed things myself. Often there is an "opaque" (billing) construct behind it that is deliberately kept complicated. But sometimes it also makes sense (ecologically and economically)

According to the supplier, with the one-time costs incurred (which have to be paid anyway) + the approximately €120, you get an "all-inclusive package." In other words, no maintenance, repair costs, etc. Apart from that, the house provider will then waive nearly €9,000 from the house price since I don't need his heating system. For me, it is actually clear that I should make the "deal" with the supplier. But as I said, I am a layperson, heating technology is important after all, and it can't just be changed overnight without a financial disaster, so I wanted to get a few opinions :-) Apart from that, a brine-water heat pump is supposed to be somewhat more efficient than an air-water heat pump, right?!

We have already discussed this topic before. The conditions should be examined very carefully.

do you have a link to the old process? the problem is simply that we probably have to make a decision in about 4-6 weeks and, as everyone here (probably knows better than I do) knows, there are still various other decisions. but before I know which technology is appropriate, it will also be difficult to proceed

Apart from that, the house seller then deducts almost €9,000 from the house price since I don't need his heating system.

With maybe €50 monthly additional costs compared to your own heating system, you can calculate for yourself whether and how the offer is worthwhile. 15 years until you break even in terms of costs. And then, in the scenario where you buy your own heating system at the beginning, you will probably need a new heat pump.