I know you'll likely be talking to Don tomorrow, but I'm sitting here looking at your figures and wondering if you missed more than those two walls you mentioned later in the thread. R13 and R19 in Philly? Are you talking floors, walls, or ceilings? I would think you'd want more than R19 between you and an attic in Pennsylvania.
Check to be sure you accounted for every window, every door, insulation between first floor and basement, ductwork in conditioned spaces or not, etc.
Roughly speaking, 5 tons seems too large for your square footage and geographic location, but 3 tons would on the other hand seem to be pushing undersized territory.
I'm sure Don will walk you through it fine. He's got a great product, and you can't beat that kind of customer service.
Building Physics Rule #1: Hot flows to cold.
Building Physics Rule #2: Higher air pressure moves toward lower air pressure
Building Physics Rule #3: Higher moisture concentration moves toward lower moisture concentration.
i thought i could have missed something else also,.the house was exististig cape cod on slab. i knocked the existing down to the slab and built new 2 story with attic,..1st floor 2"x4" walls (r13) 2nd floor 2" x 6" (r19)
ceiling is r-30. i will call Don at lunch to review the load calc. i agree this has to be the best customer service i ever expearenced!,.....matches the product, great program, great customer service!
thanks for the input,..mike
With the numbers given , why did we come up with so many different ideas on the size of this system?
BTW , I am glad to hear that this guy actually BOUGHT the hvac calc from don
Me to Ct2.
Looking at the sensible load for cooling and comparing that to the sensible capacity of a 3 ton unit, it should be fine. Even when adjusted to 25k.
I am having a hard time with the heating side though, 36k sounds awful light for Philly. Gosh, I was thinking, a 3 ton HP would be killer here with a balance point around 20. (guess)
Cape cods can be tricky, I always wonder how you do the second floor, wall hight, type of ceiling etc. Because those knee walls are actually like a ceiling during cooling season (can be 130* on other side) and exterior walls in heating (typical attic). I was putzing around with Wrightsoft and still dont think its clear.
Doc,.."the house was existing cape cod on slab. i knocked the existing down to the slab and built new 2 story with attic,"
the house is now a 2 story colonial with a full 2nd floor plus attic above,. with a finished 10' wide x 32' long finished room in middle of attic with the long walls exposed on outside to attic eaves (knee walls), treated as exterior walls as per program instructions, but i see what you mean about the attic eaves in summer being upwards of 130 degrees,....
thanks for thoughts and input.,..mike