I would add: make sure that your system has a mechanism (system humidifier, say) that will maintain a reasonably high indoor humidity -- increase heat-carrying capacity of interior air, improve heat distribution through your spaces and reduce heat loss.

I don't have any idea of what optimum levels are, but I just fire up a full tea kettle when I want to warm things up a bit.

As a past and possibly future resident of a boat, I dealt with the reverse problem -- forcibly venting interior air to the outside to take humidity with it.