I am trying to install a bathroom fan. The fan has an outlet port for a duct, which I need to connect to the existing ductwork.

The outlet port is a round rigid metal piece. You're supposed to attach a duct or adapter to it. I tried to get the diameter with a ruler and it was about 5.6in. I thought maybe I measured wrong, so I used some string to get a precise circumference and divide by pi. It came out 5.85in.

Home depot (not where I bought the fan) sells mostly 4, 5 and 6 in ducts and reducers. I saw labels for 4.5 and 5.5 but they were out of stock.

What am I supposed to do with this? Is there some obscure 5.85in adapter somewhere I need to buy, or do I just squeeze a 6in duct around it somehow?


1 Answer 1


5.85" = 6" for a duct connection. Just follow the code by installing 3 evenly spaced sheet metal screws to prevent the joint from moving. Now use aluminum tape on joint. The sheet metal screws guarantee that the tape won't break over time. You can even trip over it a couple of times in the attic without any dire consequences.

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