I live offgrid in a campervan and do not have HVAC in the normal sense. I follow mild weather, aiming for daily highs of 65-70deg F. Because I camp in arid regions this usually means overnight lows of 35-45F. I try to avoid overnight freezes for comfort and to protect my water system.
My roof vent is set to 65F (comes on then and tries to hold that temp). The LiFePO4 battery bank is warmed to 50F. At night I use an electric blanket and dogbuddy to stay warm if needed.