Getting the Right Flow - 18 Inch Flex Duct CFM Basics
Figuring out the actual 18 inch flex duct cfm for your HVAC system can be a bit of a headache if you're just looking at a standard chart and hoping for the best. While those duct slide rules and online calculators are a great starting point, they don't always tell the whole story about what happens once that giant tube of silver plastic is actually hanging in a crawlspace or attic. If you're looking at an 18-inch duct, you're likely dealing with a pretty significant amount of air—usually the main trunk line for a large residential unit or a decent-sized commercial setup. ...