I've been trying to read up on HVAC duct sizing and whatnot. Phew. It's not as easy as I would have thought!
I'd love to have someone that knows this stuff to look over my existing layout and tell me if it seems reasonable, or if I should be planning tweaks.
We'd like to add A/C someday. I believe zoning will be required for that, to avoid sending all the cold air upstairs, since we have a single zone currently.
Also, our office and bathroom are very cold. Granted, it's 15 degrees outside, but clearly, there's something not quite right with that leg. That part of the house is sitting a few feet over bare earth. It doesn't look like there's any insulation on the floors, but I see a bunch in there, up against the walls and edges of the floors. The ductwork leading in there is insulated with a single 1" (or so) plastic backed wrap (grey). Not convinced it's anything great. I feel only a weak flow of mildly warm air in there.
I've started wrapping the ductwork in the unfinished basement.
The furnace is a Trane XV90.
I'd appreciate any feedback!
Attached is the layout that I plotted using Sketchup, and it's pretty acurate, including sizes, lengths and layout. I could provide the actual sketchup file, if desired.
The super wide duct below the "16 inch label" is a 24" x 8" return. The other return is directly above it in the diagram, with the 3" vertical rise at the end. These are both in the central hall.