HVAC cost question
I am in the process of building a new home which has 3 levels (basement, 1st, 2nd) The HVAC company has sized the system to have 3 zones with 3.5 tons, 2 tons, 3 tons systems. I know there could be a lot of variability here but on an average what would be the cost (or a range) of such a system. Heat - Natural Gas. I am trying to find how much credit I should expect if I switch to a Geotherm system.