Couple Qs for ya:
What kind of windows are in the apt?
If non low-e then you can put plastic over them to help somewhat.
Hows the seals on the door(s)? Foam weather strip helps alot and is cheap.
Some fridges really suck the power. Friend of mine's wife got a "free" fridge for the garage. His wife stuffed it full of stuff they never eat or use and his electric bill went up $35 per month. Because she wouldn't get rid of it or stop "using" it he slowly emptied it out over a period of several eventually unplugged it. Electric bill dropped $35 per month.
