Really depends on the construction and that is where the manual J comes in. You have some real heat gains with a 2 story & lots of glass. It would be beneficial to have a local do a heatload for you. A lot less money than having the wrong size unit and unhappy wife for years to come. With that big sqft split you may consider two systems too. If you don't want to go that route it is usually 400 sqft per ton here in s fla. See if there is a local Johnstone Supply in the area, if you have one that does not lock out non-tradesman you should find what you need. Besides Goodman A/C is made in Tx. Good luck Been more than a few years since I did installs but a cheap ductulator (slide rule for duct sizing)will give you the duct size. Use .08 for the multiplier on the ductulator for quiet ducts. Return air grilles are 144 sqin per ton less they get noisy.

Well, I met with a 3rd HVAC pro yesterday.....and I am now more confused. The manual J calculation that he performed is vastly different from pro #1. Pro #3 suggests a 2-ton unit for basement, and 2 3-ton plus a 4-ton unit for the main level (12 tons total, compare to 7 tons total from pro #1) The load values vary so much between the 2 manual J reports, yet both professionals used the same software. How is the consumer supposed to sort through this information? Pro #3 accounts for infiltration values and duct loads that were much higher than Pro #1. Suggestions on where I go from here? Is there a simple way for me to understand the Manual J report, so that I will know which pro may have calculated incorrectly?

I suggest separate systems for the first and second floor. That is the best way to have even temperatures on each floor. It costs more up front, but you potentially have lower operating costs. You could zone the loft off the second floor system. However if you are going to be working 10 hours days with multiple pieces of equipment generating heat then spend the money on a mini split.

Thank you all for the responses. In short, based on responses here and some more research sounds like it doesn't pay to go with a mini split for a 3200 soft home (that's without the basement) + I think the look is too aggressive and trying to keep a clean minimal look.. even the ceiling cassette units that are relatively minimal stand out a lot... I think ill stick with a gas HVAC system and use coil so the air won't be as dry in the winter and also install a dehumidifier to have it nice in the summer... I did want to have a DAMPER for each room but was told that it can create issues and I need to limit each zone to maybe one or 2 damper tops per zone otherwise the unit can start icing and causing issue as they get "chocked" As for geothermal, My architect did tell me to look into it but once again don't know if it make sense for me. Don't know anyone who has it and its seems like it would be adding a big headache with starting to dig again..... @Ray Austin Thank a lot. I'm hearing this a lot where it will take so many years for me to see a return on investment and probably docent make sense... @mike_home yes I have gas and I will be using gas for the HVAC & domestic water. @Steve Greenberg I was explains that one outdoor unit will be able to handle about 4 zones but it seems per the comments here and other research I did for a house of api 3300 sqf it doesn't make sense finically to go with the mitzubishi + I'm not crazy about the look of them (cassette units) Im also concurred that the. entire house as a whole won't feel as comfortable (temp controlled) when there are so many individuals zones. BTW I was told they can work until -13° but in the nyc area we down really get to those temps.. @fsq4cw I wanted to to floor radiant but its going to be very pricy to do my entire home.. so with no choice I have to let it go.. as for Air-to-Water technology im concurred going with something that is not well known and don't have experience with... @sktn77a this is my findings as well and think I will stick with HVAC and maybe add to each zone (level) a dumper to 1 or 2 rooms per zone. was told that having a dumber in each room can cause the unit to choke and create problems like icing... @tangerinedoor you actually strengthened my fears of being concurred that the entire house or level will not be air conditioned evenly if doors not opened and/or installing another system (CERV)... leading me to stick with HVAC im curious to know how much more expensive was the mini slipt vs an HVAC assuming you got a quote in HVAC. not in dollars and cents but in percentages..