I suspect fraud with system - catastrophic. Anyone reading this who has ordered windows from Deutsche Fensterbau should consult a lawyer as soon as possible. Anyone who is blinded by the positive online reviews should be warned - I strongly believe that most of them are bought.
If you take a closer look and especially read bad reviews, you will recognize recurring patterns: Until the order is placed and especially the down payment, the company presents itself as professional, reputable, customer-oriented and extremely responsive. After that, communication - if at all - is extremely slow. The contact persons changed constantly, no one felt responsible for anything. I suspect that they are deliberately playing for time when it comes to order processing. I have not yet been able to identify the reasons - either they are speculating with the down payments on the capital market for as long as possible or the company has massive liquidity problems and lives from hand to mouth.
However, there is one thing I have to emphasize in an extremely positive way: The cancellation and legal departments of Deutsche Fensterbau really work in an exemplary and professional manner. This seems to be the real core of the company. Here you get fast and professionally sound answers why an order cannot be executed and still no refund of the deposit is possible. If you like litigation and have always wanted to do a law internship, Deutsche Fensterbau is the right place for you. In my experience, anyone who wants new windows quickly and easily would be better off looking elsewhere.