Planning underfloor heating with heat pump requires instructions

Hello, We are building a house with a general contractor. We are getting an air-to-water heat pump from Tecalor (TTL 6.5 ACS) For the underfloor heating, I said I don't want any ERR and the heating load calculation should be done for each room with the desired temperature at 30° flow temperature. The seller had never heard of this and said I should speak again with the specialist for it. I am now looking for some checklist or instructions explaining why and how this works even without ERR. Is there something like that?

has gone through the topic, otherwise use the search function with EER

Just google [Ingenieurbüros], there you will find everything you need.

Yep. I would also go with my own engineering office (it's needed anyway, for the exemption) and then give the data to the plumber for execution. Hopefully the general contractor will cooperate...

Yep. I would also go with my own engineering firm (it's needed anyway for the exemption) and then give the data to the plumber for execution. Hopefully the general contractor goes along with it...

Which exemption is this about?