Okay, a friend has built an addition to his home...a 24' x 30' family room area.
The temptation is to simply tee off the existing duct work from the existing house, and extending it to two boots/registers in the new space.
...I got a feeling this should be thought out a bit more. I am thinking:
1) find out how much heat/cooling is required in the new space.
2) figure out the air flow reqs (ie CFM)
3) find out if the existing furnace/AC system has the heating/cooling capacity, and if the supply fan has the 'oomph' to make it out there.
Any comments, suggestions?