We've been Siemens fans for a long time. In a new build we selected all Siemens kitchen appliances and are happy with them, except the rangehood. It does the extraction fine but it is constantly 'popping' with any breeze. It seems the one way 'flaps' are constantly blown open and close with a loud poppping/clicking sound. This has been a continuous and tortuous issue in an otherwise quiet house. Overnight we've started turning the fan on the lowest level to keep the flaps permanently opened. This happens regardless of how much we open or close windows and even with the faintest of breezes. We'll have to look at uninstalling it to try some retrofit repair or find a replacement.