> And for actual ducts you'll want to use foil-tape because temperature changes wreck the adhesion of duct-tape, then the moisture leaks into the walls/ceiling

> And for actual ducts you'll want to use foil-tape because temperature changes wreck the adhesion of duct-tape, then the moisture leaks into the walls/ceiling which is $$$$ bad. This strongly depends on the type of duct. Flex ducts that are a plastic skin over a wire coil don't work so well with aluminum tape.