RISMEDIA, June 9, 2009-(MCT)-A big energy hog in the house is the refrigerator, but so is the central air conditioner. Although central air conditioning is on only a few months of the year, the annual cost can be much greater than the annual cost of running your refrigerator.

You can get a very rough idea of what it costs to run your air conditioner by comparing electric bills from a spring month when you aren’t using it and a summer month when you are. Multiply the difference by the number of months you use your air conditioner to arrive at your approximate annual cost.

Replacing an old refrigerator or air conditioner can save you money every time you use it.

For example, if your refrigerator was bought before 1989, it probably costs about $148 a year to operate; a new one will cost $36 a year, under current efficiency standards. If your central air conditioner is more than 10 years old, a new Energy Star-rated one will cost at least one-third less to operate.

In both cases, the savings from improved efficiency will defray, if not completely cover, the cost of buying the appliance.

Information from Lawrence Berkeley Laboratories, U.S. Department of Energy