Inside lights left on in the summer add to the AC load, but reduce energy consumption by your heater in the spring, fall (depending on when your heat season starts) and winter. However, this heat is more expensive than most heating appliances.
If you have a single handle faucet, do not need hot water and do not move the handle to the far right, you waste hot water with every usage.
The lower the temperature on your water heater the less energy you waste from water left in the hot water lines after each use. Additionally, the greater the temperature differential between the devices location and the set temperature, the more $ it costs to operate.
Every home usually has enough inside residual heat and insulation to compensate so that temperatures outside less than 72 will not require heating or cooling the home. Anything inside the home that uses electricity or burns gas/oil adds to this residual heat. Examples: refrigerators, ranges, computers, light bulbs, hair dryers, TV's, and even bodies. This makes most home's have a "sweet spot" outside temp at which the home requires no heat or AC, usually in the 60's. This difference we will call the IRH-OT (Inside Residual Heat- Outside Temp) nominal temp.
For every degree you lower your T-stat in the winter, you can save a significant amount of money. Example: If your home's IRH-OT nominal temp at 72 is 65 and the outside temp is 45, dropping your T-stat to 71 will save roughly 5%.
For every degree you raise your T-stat in the summer, you can save a significant amount of money. Example: If your home's IRH-OT nominal temp at 72 is 65 and the outside temp is 85, raising your T-stat to 73 will save roughly 5%.
In many homes older than 30 years, insulated low-e windows and extra attic insulation can usually increase efficiency substantially.
An exhaust fan run more than necessary wastes a lot of money. This is not from the electricity to run the fan but having to replace the conditioned air you just sent back outside.
A wood fireplace with no outside air supply actually uses more energy than it produces. It burns conditioned air that must be reheated, and puts off less heat than that used to reheat the air loss. The room it is in is warmer, but all others will be cooler.
Heat pumps don't produce any heat on their own, they just transfer heat from outside air into inside heat. At temps above 40, a heatpump with a fossil fuel backup is usually the cheapest heat available. Once temps get below 40, many heat pumps become somewhat ineffective.
There are now heat pump like water heaters. These can also cool the area they are in such as an attic, basement or garage.
A common 5kw generator can power up most homes completely in non-AC season, if the major heating appliances such as water heater and furnace are gas or oil. These generators can be purchased for between $500-$800 depending on features. Many will run for 7-15 hours on a tank of fuel. They can be installed by a qualified electrician for back up purposes.
CFL light bulbs will reduce your lighting bill significantly. Please dispose of properly.
If your vanity lights are too bright or too dim, try mixing them. A 40W and 25W bulb placed beside each other in a light set will usually not be noticeable.