This undated publicity photo provided by NADCA shows a technician using a brush to clean ductwork. If you want to freshen up the air in your home and make your heating and cooling systems work more ... more 
This undated publicity photo provided by NADCA shows a technician using a brush to clean ductwork. If you want to freshen up the air in your home and make your heating and cooling systems work more efficiently, you might consider having the ductwork cleaned. (AP Photo/NADCA) less 
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Associated Press | Photo By NADCA
Wed, Feb 13, 2013 8:56 AM EST