Recently went through this and I settled on Senville 18K and 33K BTU Aura series single head units (Arctic, -22F). I live in Maryland so we see pretty low temps in the winter (lower than NC) but it's unusual to get below 15F.
Total equipment cost:
$4,165.74
1x SENA/18HF 18K Unit
1x SENA/33HF...