I got my first bills and I started seasons on my game in late fall I turned on my thermostat to warmer costs more and my bill was $26,000!! haha (note to self set therm at cooler cost less!!)
I started with a fairly new save and a very small house, and just finished Spring and Summer - with the AC on for most of summer, the bill went from around $250 to $500 (and as well, there was a lot of new artwork in the house) so not outrageous.
Does auto-lights really affect the bills? I never thought there was a correlation.