Hello,
... - architect's idea. It can really look good, but it just doesn't quite comply with the regulations...
Then that's on his "cap."
... For example, I build to KfW 75, the tender states KfW 40, ...
KfW 75 is not available for applying for funding! If KfW 70 is not achieved, it is an Energy Saving Ordinance standard building with primary energy results between the Energy Saving Ordinance standard requirements and KfW70.
A higher primary energy standard of the building, e.g. KfW 40, is associated with significantly higher costs and a completely different system technology. The architect cannot simply change things at his own discretion.
Whether a "Schwedenplatte" is the "real deal" is highly debatable!
...How do I recognize a competent architect and how do I know when I should look for another architect?..
For example, by communication. The
successful completion of a construction project is based on the trust relationship between the client (AG) and the architect (AN).
If this is recognized as disturbed, one should change before bigger problems arise, which is not entirely easy (existing contract).
The area of heating, domestic hot water preparation, and possibly ventilation should be viewed very critically. Here there is usually a lack of solid basic investigation as well as exact planning and dimensioning. Often this problem is passed on to the contractor with the motto "just build a heating system."
The client usually ends up with the short end of the stick later in the form of excessive consumption and/or investment costs. Retrospective corrections can then usually hardly be made with reasonable effort.
...He certainly sees the option to still build the house with 42cm stones and just make the floor plan 12cm larger in each direction....
This option always exists as long as the foundation work has not yet begun. However, the building application must be changed as the external dimensions will probably change. Statics, fire protection, and sound insulation may also change.
...I wanted to have the price difference clarified beforehand, he put me off until the tendering phase. Can you approach it the way he does or not?..
You can, but an experienced architect should be able to give a prior estimate.
Best regards,
NB:
All agreements should be documented in writing and countersigned! Nowadays, communication is often done quickly via mobile phone. Much is forgotten and later nothing can be proven!