Dan, do you see actual consumption, or design? How many actual energy bills have you seen? I'd say Ohio is pretty close to my climate, a lot closer than yours, and I've seen hundreds.
This house at 3200 sf (not 5000) should have a TOTAL monthly bill in the $120-200 range. Heating and cooling will be 1/2 of that. Less than half if built well. Less than 1/3 if he's using that high zoot modulating climatemaster.
I have clients with 1800 sf MOBILE HOMES with TOTAL gas consumption less than 650 therms. That's WITHOUT modulating equipment. You are saying this house will use as many btu as 3 of these? They aren't going to build better than a 20 year old double wide?