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 in the winter, my sims had the heating on the middle temp, and I wondered why they still had their coats and hats on indoors. yet another house they had it on high, they were complaining they were cold, so I turned it up to high, and they were happy in the t shirts and jeans. saying how toasty warm it was. I haven't seen the bills yet, not played long enough.