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Heat Pumps Provide Economic Efficiency
By Chuck Dunlap
MISSISSIPPI STATE -- Heating and cooling the home accounts for about 44 percent of a home utility bill each month, and therefore uses more energy and costs more money to operate than any other system in the house.
Heat pumps are a growing alternative to conventional electric units and a good way to save money. A heat pump can save as much as 30 to 40 percent of the electricity a consumer uses for heating and cooling the home. Both gas and electric heat pumps are available for use.
Dr. Frances Graham, a housing specialist for Mississippi State University's Extension Service, said heat pumps are a smart choice for heating and cooling the home.
"Heat pumps are an extremely efficient, economic alternative," Graham said. "Heat pumps work by transferring heat from one place to another. In the winter, the pumps take heat from the ground and air outside and transfer it inside the home. Even cold air contains some heat. The cycle is reversed in the summer months, sending heat from inside the home outdoors and leaving the cooler air inside."
Graham said heat pumps are the most efficient form of electric heating and cooling in climates such as Mississippi's, providing up to four times more heating and cooling than the equivalent amount of energy consumed. High efficiency heat pumps dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months. Ground source or thermal heat pumps are more efficient and economical to operate when compared to conventional air source heat pumps.
Some Mississippians believe that heat pumps can't work properly with the often radical weather conditions in the state, but Graham said those rumors simply aren't true.
"Heat pumps work best in areas with mild winters," Graham said. "The system works properly in areas where the average winter temperature is 25 degrees or above. In Mississippi, our average temperature in the winter is well above that number."
Heat pumps are rated for heating and cooling in terms of capacity and efficiency. Heating efficiency for air source heat pumps is indicated by the Heating Season Performance Factor. Heat pump efficiency depends on outdoor temperature. The performance of an air source heat pump in heating and cooling mode decreases with the drop in outside temperature. The HSPF is therefore higher in mild climates than in cold climates.
"Most people don't realize how much they spend on heating the home," Graham said. "It's the consumer's choice whether or not to cool the home during the summer, but there is no choice when it comes to heating the home in the winter. It simply has to be done. Heat pumps can accomplish this more economically and efficiently than most alternatives."
During the warm weather, the heat pump operates as a central air conditioner. The Seasonal Energy Efficiency Rating indicates the seasonal cooling performance.
Federal efficiency standards require that conventional heat pumps have an HSPF rating of at least 6.8 and a SEER rating of at least 10. The most efficient air source heat pumps have an HSPF rating of nine and a SEER rating of 16.
"The higher the rating, the more efficient the unit will be," Graham said. "Consumers should get advice not just from contractors, but from utility services as well, when it comes to what is best for them and their individual needs."