Share 'How Manual-J's Can Lead to Under-Sized Ducts'

It difficult to imagine something bad happening as a result of doing something we feel is so good. But here's what is bound to happen, at least a few times... A manual-j load calculation is produced by an HVAC contractor or third party. The default CFM values are left in place for the final report. This report is handed off to someone that sizes the ductwork in the field. They use the CFM number…