TGA planner with passive house experience

What does your architect actually say? Someone has to plan the house after all. You can search online for heating load calculation, room-by-room design of underfloor heating, etc. There are providers who calculate everything up to the hydraulic balancing. I am currently on vacation and therefore cannot spontaneously access the computer to give you some names. I think TGA minus Manager dot de does something like that.

I would leave it to the TGA planner. What the engineering firms are cranking out in times of the construction boom is hair-raising. They hire people who can barely hold a pencil but have no idea about practical planning. Above all, they then put your house (small and manageable compared to the large project) up for planning. I experience this myself every day (I did my training at the engineering office). Find yourself a good craftsman with good reviews. He can also plan.