I heat my room to 82 degrees because I keep numerous animals. It's easier to keep stable temps and less stressful on my end worrying.
I think, and it'd be a guess, my electric bill went up anywhere from 240 a year to 480 a year. Between 20 and 40 a month. But that's also heating 8 cages with flexwatt on a thermostat.
mine did a little but not that much i do know the ac stays on longer cause of the heat the lamps put out but i have them on tstats so there are off and on and off again