@Pᴀᴜʟsᴛᴇʀ2 Thank you. We got a "Corona relaunch" tax reduction for residential energy retrofits. So we try to use that chance and fit in as much as possible. As a consequence I spend plenty of time with engineers and contractors.

@Martin - Always in favor of tax reductions, in whatever form they come. Looking forward to the pics :o)

Especially in that case: 110% that means I can deduct more than I invest

awesome sauce