Im tired of the window units in my 1940's farmhouse. Ive got a 3 ton package unit Im installing. So far Ive just gone through the unit making sure everything was good with it, changed out all the insulation inside the unit, poured a concrete pad for it to sit on, and starting gathering material. Man HVAC stuff is expensive. Even with my 10% military discount at HD Im going to end up spending right close to $2K on materials. I had a local company give me a quote on doing everything and it was $5400, SO, Im doing it myself. My house is 1150 sqft and Ill have 8 drops to rooms.
Im going to be running all flexible ducting with R8 insulation. 18" for starting out for return and 16" starting out for supply. Ill be going up the wall outside and into the attic, building an insulated box around it up the outside wall.
For the return, Im starting with an 18" R8 flex duct and then Y'ing into two 14" flex ducts going to two 20x25 return boxes and grilles. Im confident on the return side.
The supply side, without being able to do all the tests the pro's do to check resistance and flow and all that other crazy stuff, Im really just guessing. Ive planned it where the cfm's are correct going through the system with the different sizes but that's about the most I can do.
Has anyone ever done something like this themselves? A couple of things im not sure of are
Which size register vents to use for the drops
The 10" drop Ive got running to my LR would it be better to have a single 10" to a vent or Y that off to two 8" vents or would that make a difference?
The blue number is the size of the flex duct, the black is the cfm that duct carries. I think I have it balanced ok.
SUPPLY- 16" flex duct from unit, up wall into attic, then branching down to 14-12-etc.
RETURN - 18" flex duct from unit, up wall into attic, then Y's into two 14" flex ducts running to two 20x25 return boxes.