Something quite isn't right, or I'm an idiot.... I put in $8.14 per "Unit" of natural gas (my current cost). One "Unit" of natural gas is 1000 cubic feet, which on the _low end_ contains more than 1,000,000 BTUs (in practice, it's more). That's $1068 doll hairs a year @ the 85% efficiency of "last generation" furnaces from yesteryear.
The newest Natural Gas furnaces are so efficient, that the exhaust pipe is just plain old PVC pipe, not metal, because nearly all of the heat is extracted. These run around 95% efficiency. Sticking that into the calc, that comes out to $971 blonde ones.
What am I missing