Duct Cleaning Revenue Center

HVAC Air Duct Cleaning
The U.S. EPA says, “Duct cleaning generally refers to the cleaning of various heating and cooling system components of forced air systems, including: the supply and return air ducts and registers, grilles and diffusers, heat exchangers, heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing, and the air handling unit housing.

Trained Professionals
“If not properly installed, maintained, and operated, these components may become contaminated with particles of dust, pollen or other debris. If moisture is present, the potential for microbiological growth (e.g., mold) is increased and spores from such growth may be released into the home's living space. Some of these contaminants may cause allergic reactions or other symptoms in people if they are exposed to them. If you decide to have your heating and cooling system cleaned, it is important to make sure the service provider agrees to clean all components of the system and is qualified to do so. Failure to clean a component of a contaminated system can result in re-contamination of the entire system, thus negating any potential benefits. Methods of duct cleaning vary, although standards have been established by industry associations concerned with air duct cleaning. Typically, a service provider will use specialized tools to dislodge dirt and other debris in ducts, then vacuum them out with a high-powered vacuum cleaner.”

EPA says that you should consider having the air ducts in you home cleaned when:

There is substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system. There are several important points to understand concerning mold detection in heating and cooling systems:

Many sections of your heating and cooling system may not be accessible for a visible inspection, so ask the service provider to show you any mold they say exists.
You should be aware that although a substance may look like mold, a positive determination of whether it is mold or not can be made only by an expert and may require laboratory analysis for final confirmation. For about $50, some microbiology laboratories can tell you whether a sample sent to them on a clear strip of sticky household tape is mold or simply a substance that resembles it.
If you have insulated air ducts and the insulation gets wet or moldy it cannot be effectively cleaned and should be removed and replaced.
If the conditions causing the mold growth in the first place are not corrected, mold growth will recur.

Ducts are infested with vermin, e.g. (rodents or insects); or
Ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers.

The EPA says what you should expect from an air duct cleaning service provider is the following:

Open access ports or doors to allow the entire system to be cleaned and inspected.
Inspect the system before cleaning to be sure that there are no asbestos-containing materials (e.g., insulation, register boots, etc.) in the heating and cooling system. Asbestos-containing materials require specialized procedures and should not be disturbed or removed except by specially trained and equipped contractors.
Use vacuum equipment that exhausts particles outside of the home or use only high-efficiency particle air (HEPA) vacuuming equipment if the vacuum exhausts inside the home.
Protect carpet and household furnishings during cleaning.
Use well-controlled brushing of duct surfaces in conjunction with contact vacuum cleaning to dislodge dust and other particles.
Use only soft-bristled brushes for fiberglass duct board and sheet metal ducts internally lined with fiberglass. (Although flex duct can also be cleaned using soft-bristled brushes, it can be more economical to simply replace accessible flex duct.)
Take care to protect the duct work, including sealing and re-insulating any access holes the service provider may have made or used so they are airtight.
Follow NADCA's standards for air duct cleaning and NAIMA's recommended practice for ducts containing fiber glass lining or constructed of fiber glass duct board.

Regarding consideration of duct cleaning contractor the EPA recommends that they be asked if they:

Are experienced in duct cleaning and have worked on systems like yours;
Will use procedures to protect you, your pets, and your home from contamination; and
Comply with NADCA's air duct cleaning standards and, if your ducts are constructed of fiber glass duct board or insulated internally with fiber glass duct liner, with the North American Insulation Manufacturers Association's (NAIMA) recommendations.

Clothes Dryer Vents
Related to duct cleaning is the issue of clothes dryer vents. The U.S. Fire Administration National Fire Data Center (January, 2007) said that “Failure to Clean is the #1 contributing factor to clothes dryer fires.” The reason? Lint and debris can build up in the clothes dryer vent over time. They block air flow and create potentially hazardous conditions including the possibility for an exhaust fire or carbon monoxide intrusion (gas clothes dryers). The U.S. Fire Administration, National Fire Data Center reports that, “There are over 12,700 home fires per year associated with clothes dryer fires resulting in 15 deaths and 300 injuries, and 88 million dollars in property loss.”

A dryer vent exhaust system carries water vapor evaporated from the wet clothes in addition to lint. The lint may be comprised of highly flammable particles of clothing made of cotton and polyester. The accumulation of lint can reduce the dryer’s ability to expel the heated water vapor. This results in the accumulation of heat energy within the dryer. Mechanical failures such as the limit switch, damaged lint screen, thermostat, of crushed exhaust hose) can trigger sparks that can cause the trapped lint in the dryer vent to become ignited.

To avoid this potential hazard the customer should ask the air duct cleaning service provider to check out the dryer vent system and clean it if necessary.