Prefab house from Hartl Haus or Elk Haus?

Doesn’t anyone here have experience with these two companies?

Counterquestions: why the decision for prefabricated construction, or only the two Austrians in the selection (Bavaria also has several providers, and Baden-Württemberg wouldn’t be far either)? Here there is only a small part of the builders in the forum from Austria, even fewer of them build "prefab" and Germans who (only) ask about two Austrians are even rarer. That means you will get some answers to this very specific question here if you have three years of patience. This topic is not a quick deal here. I looked at both websites again yesterday (and otherwise rarely): with both I can well imagine satisfied customers, but a) I don’t know any (not even from the forum) and b) I trust several other providers just as much. Regarding heating technology, I would let every provider do what they have the most experience with; or if I wasn’t fond of this technology, consider another provider; but under no circumstances go to a provider and then be a guinea pig for something they rarely install.

Thank you for the answers!
At the beginning, it was not only the two Austrian prefab house companies in the running! German ones, including Weberhaus, were clearly more expensive (except for Schwabenhaus, but there the overall concept or the approach somehow did not fit)! Since we do not live far from the Austrian border, Austrian companies are also an option. The salesperson also makes a big difference! If you don’t get along with one or if the chemistry between the salesperson and the builders doesn’t fit, then it simply won’t work out with the company.
In any case, now only the two offers from the Austrian companies remain.

Is there also an Austrian house building forum?

Energy-saving house dot at

In FB there is an ELK-Haus group with 1700 members.

It was not only the two Austrian prefabricated house companies in the running at the beginning!

And no solid builders at all?

Unfortunately, I cannot report anything positive about Elk. It's not that the chemistry wasn't right at the beginning. But Elkhaus's behavior changed completely after the contract was signed. Very long response times and suddenly no one could remember any verbal agreements. Very disappointing. I can only recommend having everything from Elk Fertighaus checked by lawyers before you sign anything! Our lawyer scolded us heavily for not having it checked thoroughly beforehand, as there are definitely some pitfalls and ambiguities built in! So be careful.