Experiences with air-water heat pump in KFW55 city villa with ventilation (heat recovery)

Good morning dear house building community, Our city villa (9x12) is now fitted with windows and thus the rough-in plumbing can begin;) Regarding the heating: The plumbing company has selected a 12 kW AD from Weihaupt for us... Seems very or rather too large for 260m² - among other things because of the ventilation with heat recovery from Zehnder (450) and underfloor heating... What do you think? What information is needed besides a heating load calculation, which the plumbing company does not carry out?! Is there anyone who has something comparable for this air-water heat pump? PS: Tips on noise levels from practical experience are also welcome:)) Best regards Hessy-J.

Heat load calculation is the right keyword. It must be done, otherwise the heating engineer will choose the wrong device size and it will become uneconomical for you. True to the motto, as long as it's warm.