Although I have always been good about taking care of my HVAC system I neglected the duct system. Because the duct system is concealed inside the walls and crawlspaces I never gave it a thought. I made sure to schedule professional maintenance for the HVAC system every year. I changed the air filters every month and even kept up with the cleaning of the supply and return vents. It simply never occurred to me that contaminants were likely building up in the ducts. Since the heated and cooled air passes through the ducts many times a day the condition of this network of pipes is extremely important. When things like dust, pollen, bugs, webs and even decomposing rodents accumulate inside it blocks airflow. This causes the HVAC system to run for longer cycles to manage the thermostat settings. Longer cycles results in greater wear and tear on components and higher energy bills. Also diminished airflow impacts comfort. There were cold and hot spots throughout the house no matter how high or low I adjusted the thermostat. There is also the concern of degraded indoor air pollen levels. When there is contaminants and mold inside the duct system it gets introduced into the air every time the HVAC system starts up. When I realized that my whole family was complaining of headaches and sneezing whenever the HVAC system ran I knew every one of us had a problem. I hired my regular HVAC company for duct cleaning service. The process was surprisingly quick and caused no mess or damage to the house. Although it was rather costly the duct cleaning has significantly reduced the cost of my monthly energy bills.