Understanding what goes into monthly charges could give you a better idea on how to reduce wasted energy and unnecessary expenses. Cost and results may vary depending on the type of heating or cooling systems used. In most cases, the biggest share of a household’s energy use generally goes to heating and cooling. The average annual bill for a home equipped with a gas furnace and central air is about $875, which is about 43% of a year’s total energy spending.  In total, your use of appliances could be costing you $250 or more per year. If your refrigerator is old or if you have more than one, that’s usually the biggest issue. Water heaters alone tend to be the third largest energy consumers trailing behind heating and cooling units...and lighting usually accounts for about 12.5% of the overall bill.