/Bought goodman furnace and ac. want to install my new system. How do I decide on duct work size and reduction for adequate air flow? Will install units myself and get pro to do hookups. Wonder if gas company will hookup instead. Figure 60k btu and 2 ton a/c for second floor addition (3br, 1 bath added) about 900 sq. ft including hall and stairway. All four rooms on same back side of house, hall on front side as access to them, i.e. straight run 40 feet long.
duct work in hall feeding all 4 rooms. Can fit 8x16 duct to start and reduce as necessary. What to do?
You are trying to learn in one e-mail stuff that AC guys take months to learn. There is more to it than just starting a piece of ductwork and making periodic reductions in size, because you have to know HOW bit to make the branches based on the room's requirements and the distance from the main. You MIGHT be able to get an AC person to make your calculations and design, assuming he has enough work so he didn't care if you did it yourself.
Yes indeed, the duct design manul is over 200 pages long and that's just the residential section.