I've posted here a lot lately, but I will summarize what I am doing. Installing a new propane furnace, current one is 90k input 90%, and I know it is too big. I have had several HVAC guys in to quote, some did calcs, others did not. Left me confused because even the calc guys were all over the place. I plan on having a Goodman modulating furnace put in. I purchased the software from above, and carefully worked it through. Very carefully. On "average infiltration" the calc came back 63K. On "tight" it came back in the 50's. I used a design temp of -5, since on a normal winter we get that at least at night fairly often (the software suggested +5)
I am not sure what to use for the infiltration.. The house was built in 1990, average construction grade. We have lived there since 1999 and I have sealed and caulked, added storm doors, and I also put plastic on most of the windows in the winter (huge difference) I know it has a Tyvex wrap, but who knows how well? I am in the heart of the NE Ohio snowbelt, and we get pretty good winds coming across the huge cornfield during the winter.
What do you all suggest at this point? Thanks, Mike.