I have heard that over sizing the vertical loop up to 20% can reduce the auxiliary heat usage. How can I calculate the energy savings to determine if the added costs can be justified? I am located in Cincinnati, OH. Currently have two-gas furnaces/ac, one for the 45 yr old slab portion and one for 12 year old addition with walk out basement. I need a total of 5 tons (3 ton in basement for addition and a split system with heat pump in basement with refrigerant line through wall to air handler) for slab part of house. I could drill 6-150’ wells with ¾” pipe or 3-300’ wells that would require 1” pipe. I understand the 300’ wells have additional costs, but would the energy efficiency increase enough?