Our AC broke and my mother was really cranky in the hot humidity of VA. So she just wanted to get something into the house and get cool again. I sent her a ton of links to ACCA website, NATE certification website, and printed off the checklist for a manual J installation so that she could make sure the contractor was doing it right. But i dont know if he did a load calculation or not. He gave us a Carrier unit, 21 SEER that jumps from a 2 ton to a 3 ton depending on the work it needs to do to stay cool. Now that we have this super piece of equipment, what do i need to do to make sure that it is working as efficiently as possible? What about mini-duct air distribution? because i am sure we are losing a lot in old ductwork. Did we just waste a ton of money?