Re: How to size ducting in a new home?
Make, model, and serial # please... just kidding.... kinda.
You'll have to give a lot more info before you'll get a definitive answer, but my rule of thumb is...
What ever the outlet size is, run that to distribution (sq, in, area)... after that it doesn't mater as long as the sg. in. area = or exceeds the outlet size on distribution.
On the return, run same size.
This works if you are running "smooth walled" ducts, if you are using ribbed flex ducts you might want to err on the high side.
It really all depends on the type of system you have and duct length/type.
