I have a one-story house, and it looks like it would be easy to run new ducts myself in the attic. What should I know before trying to design a duct system myself?
I have seen ductwork that's metal rectangular with a main supply trunk that has branches coming off, I've seen it made from ductboard, I've seen pre-insulated circular ducts routed all over the place with plenum connections, etc. Which of these should be considered for a house such as mine?