NADCA says a good rule of thumb is if your ducts look dirty, then they probably are and you should have your system inspected by a reputable, certified HVAC professional. Here are some reasons people decide to have their air ducts cleaned.
Better Indoor Air Quality
Your heating and cooling system is the lungs of your home or office. The system takes are in and breathes air out. Every day contaminants such as skin, dander, dust are drawn in to your system and re-circulated 5 to 7 times per day on an average and over time these build up in the duct work.
Dirty ducts do not necessarily mean your air is unhealthy, however, these ducts may be contributing to bigger heath issues or housing other contaminants that could cause serious problems for people with respiratory, autoimmune issues or environmental allergies. Indoor Air Quality
The U.S. Department of Energy says that 25 to 40 percent of energy is wasted on heating and cooling a home. Even though you change your filters, contaminants still get into your HVAC system and slow it down, make it work harder and can even shorten the life of your system. So when the system is clean, less energy is utilized, leading to cost effectiveness and energy savings. Energy Savings