Originally Posted by
Anthony Whitesell
If you can't have the exact right duct size, is it better to be the next size lower or the next size larger?
I'd go next size higher, with the qualifier that I use metal duct which is available in 1" increments. My 2hp Oneida system has a 7" port and I have 7" duct out to the major branch for the main and 6" from there. I'd settle for some slight settling over restricting max CFM...but that's a personal point of view.
--
The most expensive tool is the one you buy "cheaply" and often...