4(a). List your home energy types and costs, or track a vehicle instead

Note. A genuine either/or, and the two are quite different work. The home route needs the types of energy your household uses, how each is delivered and measured, and what it currently costs, which in practice means getting at utility bills. The vehicle route needs fuel used, miles driven, miles per gallon and trips. If the bills are not something you can see, the vehicle route is the one that works.