If your house has central air conditioning, the air conditioner will probably be the biggest user by far. Although used only a few months of the year, the annual cost can be much greater than the annual cost of your refrigerator, which is typically the next largest user. In hot climates, the annual air conditioner cost can exceed a thousand dollars. You can get a very rough idea of what your air conditioner is costing you by subtracting the electric portion of your bill in a spring month when you aren't using your air conditioner from the electric portion of the bill in the summer when you do use it. This gives you the monthly cost. Multiply this by the number of months you use your air conditioner to arrive at your approximate annual cost.
Refrigerators are typically the largest users in houses without air conditioning or in climates where the air conditioners are used only a few days of the month during the cooling season. If your refrigerator is more than ten years old should consider replacing it. New efficiency standards went into effect in 1992, and older refrigerators are typically two to three times more expensive to run than a new unit. For more information go directly to the American Council for an Energy-Efficient Economy's list of most efficient refrigerator-freezers.
We have an older house. Which should we do first: insulate or replace the furnace?
Whether you should insulate or replace your furnace first depends on the situation in your house. Factors that influence this decision are the age and efficiency of your furnace, and the amount of insulation currently present in the house.
In general it is more cost-effective to upgrade insulation than it is to upgrade your furnace. However, if your furnace is old, and you are planning on replacing it anyway, you might want to upgrade the furnace if you have to choose between the two options. The average lifetime for a furnace is between 15 and 20 years. The efficiency of furnaces has increased over the years, so the older a furnace is, the more likely that furnace is to be inefficient. The average efficiency of new furnaces has increased from 63% in 1972 to 83% in 1995. Older furnaces, and furnaces which are used a lot are more cost-effective to replace than newer or infrequently used furnaces. Also, if you insulate your house at the time of furnace replacement, you might be able to buy a smaller capacity furnace and save money on the price. The same holds true for A/C and other heating and cooling equipment.
Will installing a programmable thermostat reduce my heating and cooling consumption?