Gas boiler or air heat pump

Hello dear house-building community,

We are currently thinking about building a house.
The house-building company offers, at no extra cost, either a gas condensing boiler or an air-source heat pump (Rotex hpsu compact 304 with 4kw).

The house would have 130 sqm of living space over 1.5 floors with underfloor heating upstairs and downstairs for a 2-person household with a child who only lives in the house occasionally.

Do you have any advice for us?

Thank you very much in advance!

Hmm, then the gas boiler is too expensive. It should actually be clearly cheaper than the pump.

So, a piece of advice from you "pro" air heat pump?

What kind of gas boiler should be installed?

So, a piece of advice from you "pro" air heat pump?

Or... you can negotiate when choosing gas boilers.

Why? I can choose between gas or air heat pump, so the gas boiler wouldn’t cost anything extra. I just don’t have in mind which gas boiler it would be, since I initially thought that an air heat pump would be the better choice if I can freely choose