We are very pleased with our house design. It runs very low utility bills for Michigan. It's pretty basic;
Ranch with full unfinished basement, one ceiling level, nothing vaulted
No sliding glass doors or skylights
No fireplace
3 1/2" fiberglass in the walls and 12" fiberglass and blown in in the ceiling
Foil backed drywall serves as a moisture barrier
Old standard efficiency forced air gas furnace
Gas water heater and stove
Attached garage
Good doors and windows properly installed