Why would be a window designed, engineered and manufactured Germany the better choice?
First of all, I feel that we all have a responsibility to do as much as possible to protect our environment with energy saving products. Even more beneficial is it when we can lower our monthly bills with products that are sustainable and recyclable while having an outstanding performance and design.
Looking at the trends and the North American Fenestration Standards as well as the National Fenestration Rating Council, window requirements will increase steadily. That means that the required u-values for new construction buildings will be lowered steadily (the lower the u-value rating, the better the insulation factor).
Therefore, if you choose a better insulated window with a lower u-value in the first place, the more you can increase your monthly savings.
Lower u-values will also increase your resale value noticeably in the future since your windows already/still meet the requirements in the foreseeable future.