Heating, ventilation, and air conditioning (HVAC) systems have been shown to collect a variety of contaminants such as mold, fungi, bacteria and very small particles of dust that have the potential to affect overall health, The removal of such contaminants from the HVAC system and home should be considered one component in an overall plan to improve indoor air quality.
The best way to determine if the HVAC system cleaning was effective is to perform a visual inspection of the system before and after cleaning. If any dust or debris can be seen during the visual inspection, the system should not be considered cleaned. While you can perform your own visual inspection using a flashlight and mirror, a professional cleaning contractor should be able to allow you better access to system components and perhaps the use of specialized inspection tools.
NADCA does not endorse one kind of equipment over another. There are two main types of vacuum collection devices: (1) those mounted on trucks and trailers, and (2) portable units. Truck/trailer mounted equipment is generally more powerful than portable equipment. However, portable equipment can often be brought directly into a facility, allowing the vacuum source to be located closer to the ductwork. Both types of equipment will clean to ACR, the NADCA standard. All vacuum units should be attached to a collection device for safe containment prior to disposal. Any vacuum collection device which exhausts indoors must be HEPA filtered. A vacuum collection device alone will not get an HVAC system clean. The use of methods and tools designed to agitate debris adhered to the surfaces within the system, in conjunction with the use of the vacuum collection device(s), is required to clean HVAC systems. (For example: brushes, air whips and “skipper balls.”)
The U.S. Environmental Protection Agency says that “duct cleaning services typically – but not always – range in cost from $450 to $1,000 per heating and cooling system, depending on the services offered, the size of the system to be cleaned, system accessibility, climactic region and level of contamination” and type of duct material. Consumers should beware of air duct cleaning companies that make sweeping claims about the health benefits of duct cleaning, as such claims are unsubstantiated.
Consumers should also beware of “blow-and-go” air duct cleaning companies. These companies often charge a nominal fee and do a poor job of cleaning the heating and cooling system. These companies may also persuade the consumer to pay for unneeded services with and/or without their permission. (If you have knowledge of a practicing “blow-and-go” air duct cleaner, contact your local Better Business Bureau to report the company, and your local, federal and state elected officials to demand legislation.)