Duct cleaning is actually a misnomer; to improve your air quality and the energy efficiency of your AC system, a complete HVAC system cleaning is required (HVAC is an acronym for heating, ventilation, and air conditioning).
Duct Cleaning Affects AC System Efficiency
According to the EPA, a build up of just over four-tenths of an inch of dirt on the cooling coils can result in a 21% decrease in the efficiency of the coils. Yet duct cleaning alone never touches the cooling coils. The cooling coils are what remove the heat and humidity from the air in your home. If they are not working efficiently, your AC system has to work harder, run longer, and use more electricity to cool your home, not to mention the fact that the air you breathe passes over the dirt on these coils. Air duct cleaning without addressing the coils would be like cleaning your vacuum cleaner hose without emptying the bag; pretty much a waste of time and money. Your air ducts might be clean, but your air handler (which includes the blower, cooling coil, and plenum box, where all of the ductwork originates) would still be working inefficiently and compromising your air quality.
In our opinion, the cost of air conditioner duct cleaning is not worth the cost. Your entire system needs to be cleaned in order to reap the benefits of better indoor air quality and better energy efficiency.
The air from your home enters your AC system through the return grill, the large vent with the filter inside. The most common fiberglass filters are only 7% efficient at stopping dirt from passing through them. If they were too effective, they would also restrict the air flow to your AC, and it would have to run longer to cool your home. The air is drawn into the blower and forced through the cooling coils. It is when the air comes in contact with the chilled coils that the heat and moisture is removed. The moisture runs down the coils into the condensate pan, much the way moisture condenses on and runs down your bathroom mirror during a hot shower. Here it is pumped to the outside of your house. Since the coils are always wet, they tend to pick up the dirt in the air more quickly than a dry surface and are a good breeding ground for microbial growth. The conditioned air then enters the plenum box where it is distributed to your air ducts and AC vents. The blower, cooling coils, and plenum box are all in one unit and together are called the air handler. This is the heart of your AC system.
Not all duct cleaning services are equal.
The problem is that in many states, unless a company has an HVAC license, they are not permitted to access or clean these components. This is to protect you from having your system accessed by someone who doesn’t know what they are doing. So in these states, all an unlicensed duct cleaner can do is reach what they can from your AC registers, and the rest of the system goes untouched. So you can see that duct cleaning without cleaning the air handler components is totally inadequate.
However, entire HVAC system cleaning by a licensed company is definitely worth the cost, especially compared to the cost of not doing it. The Louisiana Coop Extension Service estimates that 9 out of 10 HVAC system failures are caused by dust and dirt. A dirty system has to work harder and run longer than a clean system. Add to that the fact that the EPA has found indoor air to be 70% more polluted than outdoor air, and that the average house collects 40 pounds of dust a year (Discover Magazine), and you can see the importance of maintaining and cleaning your system.
Start with your local BBB website to find a reputable air duct cleaning company that is licensed to perform the entire job, and begin to save energy and breathe easier.