We are building a 2900sqft home and I have been getting bids for my HVAC. My problem is that we are getting different opinions on the unit tonnage needed. We are using foam in walls, with zip board system and blown in cellulose in the ceiling and radiant barrier. We live in Tulsa, OK. Our house faces northwest with 4 windows in that direction-1 is under porch. The rear of house is southwestare and all the windows (12) are all under a lg covered porch. 2 window face northeast, and 2 sml are south facing. We requested 2 units because we like to sleep cold with good air movement and thought a sml unit for our side approx 900sqft and a larger one for the reaming 2000sqft. We also have considered just 1 unit and getting a mini-split for our bedroom. We have mostly all 9ft ceilings, but have 10ft in center in living room and kitchen. I would appreciate any suggestions because I don't know who to believe. I also want an ERV air exchanger. Thx for any advice!