Comment by bluGill

Fine, but I have already upgraded to the most efficient heat pump, and so I'm at the end of where I can go there. Likewise my insulation cannot be improved without a major remodel (My house is not built to modern standards so there is a lot of improvement, but those require thicker walls and a higher attic ceiling) and so while I'd like to do them they are not possible. What is left is the smaller things.