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!!)
Once I turned the thermostat off....the bills went back to normal....around $10-15K. They live in Oasis Springs.....so it doesn't get cold very often....but the winter in the desert gets pretty cold for them, as the toddlers were complaining. I think next time....unless my Sims are rich....they'll be lighting the fireplace and putting on jackets LOL