Which heat pump? Ventilation system / Air-to-water heat pump

Hello, my husband and I are currently pondering the question: Which heating system should be installed in the planned house? I insist on a ventilation system and a wood-burning stove in the living room. It should therefore be compatible with these. Our selected construction company has now offered us 3 heat pumps:

Air-water heat pump: Nibe F2040-8 with Nibe VVM320 ALWP: Nibe F750 P with supply air module SAM 40 Brine-water heat pump: Nibe 1245-6 with deep drilling

My husband currently favors the exhaust air heat pump because he thinks it works like the air-water heat pump, only it better utilizes the warm air from the running computers... I only read everywhere: "Definitely no exhaust air heat pump, unless you build a passive house." Does the supply air module actually make something like an air-water heat pump out of it, only that the warm indoor air is better utilized?

The plan is a two-story, timber frame construction with Kfw55 standard. I must honestly admit, I no longer understand this damned heating topic. The more information I get, the more complicated it becomes.

Costs would be decisive for your decision.

Air-water heat pump: Price x (included in the offer) - without ventilation system! ALWP: +7652€ Brine water heat pump: +6685€ - without ventilation system, but including drilling and there might be a BAFA subsidy

The house is planned for 4-5 people. Questions I received: Ventilation system probably always comes with very dry indoor air? Some of the mentioned systems have relatively small hot water tanks. Is 180L enough for 5 people? No way, right? Since we occasionally have overnight guests who obviously also shower, the question would be whether it makes sense to heat the hot water like in the current apartment simply with a tankless water heater?

What does a ventilation system cost you?

The subsidy for the brine-water heat pump would be €4500 (if you don’t mess it up - keyword: APPLY BEFORE SIGNING!!!)

The argument about the air-water heat pump is rather nonsense... you constantly draw in cold air. I would honestly make it dependent on the price of the ventilation system. The brine-water heat pump will certainly be more sensible than the air-water heat pump... just as a tendency. The difference is only €2200, which you get back after about 6-10 years. Another point in its favor is the fact that the drilling remains usable even after the heating system has died. For the brine-water heat pump, find out how deep the drilling should be - that is, how deep. At first, it sounds strange because the depths depend on your soil.

P.S.: I wouldn’t build without controlled residential ventilation.

The ventilation system is probably estimated at an extra 13,000€... I suspect the 6,685€ comes from the fact that I confronted the construction company with an offer from a local heating engineer who offers the Nibe 1245-6 including 80m drilling for about 14,500€ and I said that should basically break down to roughly +- 0 compared to the air-water heat pump.

Another argument against the brine-water heat pump and for the air-water heat pump or AWHP: with the deep drilling, inaccessible components are installed. You can't easily get to them. With an above-ground heat pump, access is easier if something needs to be repaired.

And yes, I know that I have to apply for the subsidy before signing. But we said that if it’s an option, we’ll try it, but we are not planning it in. We can still spontaneously manage 4,500€ if necessary.

Correction, ventilation system is about €6000 more... misunderstanding between my husband and me