An average space heater is like 1k-1500 watts
A 5k BTU window air conditioner uses roughly 5 amps (500 watts or so).
Dishwashers use a lot of power, and are used in different frequencies by different people, as well as hair dryers, curling irons, clothes irons, washer/dryer, all kinds of stuff.
Swap every normal bulb in your place to LED or at least CFL if you haven't already. That's just smart anyway. Be energy wise and don't splurge. Not to avoid detection, but more to keep your bill low.
Don't sweat energy use suspicion unless you're doing something ridiculous. 1kw is not ridiculous.
Back to your bill, a 1kw light will use 1kw for every hour it's on, no? So as was said, your cost per kwh (mine is about 7 cents) X hours of the day your light will be on X days in billing cycle (60 days for me).
So for me, $.07 X 12 X 60 = About $50/period for one 1kw light to run 12hrs/day
That's my understanding of the bill anyway. I don't analyze it much, I just pay it.