go to your breaker box and feel them for heat, if any are warm or hot, figure out what appliance, central air, whatever is on it, that circuit may be the culprit. Or turn off your mains and go look at your meter, it should not move at all(or hardly). This 50kwh/day is high, I use between 30-40/day it might be your Air Conditioner(s), maybe the elec. co hasn't been out to read the meter in a while and is taking it out on you, call the power company and tell them whats going on, just lock your closet and room too if they come over to look at your meter and breaker box.
Since you moved in last week, they don't know how much power it takes to run your house/habits, DONT WORRY, 250w is less than the 1 PC I have running here all day/night (not my fault)