These items are also energy hogs:
- Electric hot water set higher than necessary
- Computer(s) left on all the time
- Plasma & LCD TV's
- Stereo's
- A/C set lower than necessary (74deg s/b OK for most folks)
- Leaks in ducts (as mentioned)
- Not enough insulation
One thing not often thought of here are multi paned, low-e windows which will keep a LOT of heat out and cool air in.