It doesn’t make sense to talk about “adding up” unless we define what we’re aggregating over. Residential energy consumption, for sure, is a significant chunk of energy consumption.

If we’re looking at the things we can do to reduce our individual consumption, it absolutely makes sense to prioritize the things which are large relative to our other individual contributions, first.

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.