to add on what everyone else has mentioned, look at how much you use other appliances, especially the dryer. Depending on its wattage and how frequently you use it, it can very quickly add up (on top of everything else). I try to use mine as little as possible to save.

I have a 1200sqft house that's heated with oil and a pellet stove, and even though I only use around 400kw in the winter, the jump in price still hurts.