Which heating system for a new single-family house

Hello everyone,

we have the choice between 2 prefabricated house providers with different heating systems. I am not very familiar with the topic, so I hope for your assessments.

Basic data: living area 150 sqm in ground floor + upper floor and 40 sqm heated in the basement

Var 1: kfw40 house with Proxon fresh air heat technology - i.e. air-to-air heat pump
Var 2: kfw55 house with underfloor heating and Buderus air-to-water heat pump or Viessmann (Vitocal 242-S) air-to-water heat pump

What do you think about the advantages and disadvantages of the technologies?

Best regards & thanks

Separate controlled residential ventilation and heating.

Search for Proxon in the forum here, not too long ago.

I find Var. 2 more likeable. Air-to-air heat pump would be nothing for me.

You should consider whether you want underfloor heating or preferably warmed air. Personally, I would not want an air-to-air heat pump, regardless of the technology.

Be sure to choose a water-based heating system and plan the heating surfaces for low temperatures (max 30 degrees as a target). It is more efficient and cannot be retrofitted. Everything else leads to dissatisfaction. Whether air-to-water heat pump or ground source heat pump, both work if well planned. Air heating can be considered in a passive house.

Kfw 40 is very close to the passive house in terms of heat loss. In this respect, it can work. Domestic hot water production via air-to-air heat pump is a nightmare, as the electricity meter spins with every bath. Heated, blown-in air is not exactly comfortable either. However, it is an inexpensive solution. I would expect that variant to be 10K€ cheaper.