Exhaust systems for stove facing "down" good?

It should not go unmentioned that the recirculation systems require a 20-minute (!) after-run time so that the activated carbon filters dry and do not start to mold (this should probably also apply analogously to the updraft hoods).

For Bora, for example, it says in the BDA:

"After each use in recirculation mode, switch the cooktop extractor to a low setting for about 20 minutes or activate the after-run automatic function."!

It should not go unmentioned that the recirculation systems require 20 minutes (!) of run-on time to allow the activated carbon filters to dry and not start to mold (this should probably apply analogously to updraft extractor hoods as well).

This does not apply to all recirculation hoods. Our Berbel has only 10 minutes of integrated run-on time in recirculation mode.