Originally Posted by
Andy Giddings
Bob, if you're not getting enough flow at the power tools changing the main line and drops would give you a boost. You don't say whether your main trunk is smooth or not - I assume it is? If so, your boost is not going to be as good as changing out a long flex duct but, according to the static calc spreadsheet mentioned earlier in the thread, still around 8 in wg at 1000CFM. This boost will drop if you've got lower flow. Would certainly recommend changing both line and drops if you have the time/budget. Also go for large radius bends.