I am very conscientious about cleanliness, and I make sure that my house is neat, organized, and scrubbed. I wash all surfaces down with antibacterial cleaner, and my vacuum cleaner features a HEPA filter. I make sure to have the furnace professionally cleaned every fall, and the air conditioner serviced in the spring. When I noticed a musty smell in the house, I had some trouble locating the source. I eventually realized that the smell worsened every time I started up the central cooling system. If the air conditioner ran all day long, I ended up with a terrible headache, my daughter couldn’t quit sneezing, and my son complained about a sore throat. Although my HVAC contractor had just recently inspected, cleaned and tuned the air conditioner, I knew it was the cause of the odor and our health issues. Changing the filter and cleaning the supply vents did not help at all. I finally hired the HVAC contractor to come back for another look at the cooling system. He told me that there was most likely contaminants hidden in the duct system. Things like dust, pollen, insects, mold, and dead rodents get inside the ductwork, and every time the HVAC system operates, it spreads odors, bacteria and other air pollutants throughout the house. Plus, the buildup of debris blocks airflow, diminishing comfort, placing more wear and tear on heating and cooling components, and causing higher energy bills. The process of cleaning the duct system was not time consuming, messy or labor intensive. After the cleaning, the odor completely disappeared, my house felt cleaner and fresher, and my entire family felt better.