Answer: Because they get dirty!
In addition to normal accumulations of dust and dirt found in all homes through regular use, there are several other factors that can increase the need for air duct cleaning:
- Pets that shed high amounts of hair and dander
- Occupants with allergies or asthma
- Cigarette or cigar smoke
- Water contamination or damage to the home / HVAC system
- Home renovation or remodeling projects
- Overall home cleanliness
Some occupants are more sensitive to these contaminants than others. Allergy and asthma sufferers, as well as young children and the elderly tend to be more susceptible to the types of poor indoor air quality that air duct cleaning can help to address.
Inspect Your Air Ducts
You can tell if your heating, ventilation and air conditioning (HVAC) system needs cleaning by one of two ways. First, with a screwdriver, remove a floor or wall register. Then, use a small mirror and flashlight or use a digital camera to take a picture inside the duct. If there is visible dust, dirt or debris, you should have your ducts cleaned.
What You Need to Know About Duct Cleaning
Air duct cleaning is a misnomer. In actuality, the entire HVAC system should be cleaned. Failure to clean all components of the system can result in re-contamination of the entire system, thus minimizing the benefits of cleaning.
Just as you would not only clean half of your living room floor, you also would not want to clean only part of your heating, ventilation and air conditioning (HVAC) system. NADCA recommends cleaning the entire HVAC system, including the following components:
- Air ducts
- Drain pan
- Air plenum
- Blower motor and assembly
- Heat exchanger
- Air Filter
- Air Cleaner
Proper HVAC Cleaning Process
There are two key components to HVAC cleaning: breaking contaminants loose, and collection of contaminants.
Breaking Contaminants Loose
Properly cleaning HVAC systems requires removing the sources of contamination. Source removal begins with use of one or more agitation devices designed to loosen contaminants from the surfaces within the heating and air-conditioning system.
Examples of agitation devices include brushes, air whips, and compressed air nozzles or “skipper balls.” Agitation can also be achieved through hand-brushing or contact vacuuming.
Collection of Contaminants
During cleaning, the entire HVAC system is placed under continuous negative pressure (vacuum) to prevent the spread of contaminants. Continuous negative pressure allows very fine particles to be removed from the system as they become airborne, ensuring that these particles are not released into the living space when the system is turned on after cleaning.
This negative pressure also serves to extract the loosened contaminants, which are collected and removed from your home.
There are a few things that you can do to maintain the cleanliness and efficiency of your HVAC system:
- Get good filters—ask your contractor for a recommendation.
- Clean/change the filters as needed (at least every two months).
- Even with properly cleaning and changing quality filters, the HVAC system will still become dirty over time. Have your system inspected every two years to determine whether your system needs to be cleaned again.
A thorough cleaning can also yield long term energy savings. Research by the U.S. EPA has demonstrated that HVAC system cleaning may allow systems to run more efficiently by removing debris from sensitive mechanical components. Clean, efficient systems are less likely to break down, have a longer life span, and generally operate more effectively than dirty systems.
Duct cleaning is an essential part of home maintenance just like mopping and vacuuming. Your duct system is the heart and circulatory of your house. If any of it is gunked up with dust or mold, the core system isn’t going to function properly. Because it’s out of sight, people don’t think about cleaning the system that delivers the air they breathe.
If you do hire someone to clean your air ducts, make sure they know what they are doing. A poor job is worse than no cleaning at all because it can kick up particles or even break portions of the HVAC system. Air duct cleaning is a fragile operation, and if it’s not done right it can damage the system.