Frequently Asked Questions
The techniques to perform Air Duct Cleaning are accomplished by following an organized specification specific to a particular HVAC system. Often the method of cleaning is determined based on the accessibility to the inside of the ductwork. Access to the ductwork may be limited because of a solid ceiling, cement floor or old acoustical tiles. There may be an issue with reaching ductwork do to it's being high up off of the ground or in a difficult to access place.
We may also find obstacles that need to be addressed and worked around. They may include, sheet metal screws, air flow dampers, turning vanes, reheat coils, fire dampers, fire probes, thermostats.
Therefore the equipment that we choose to use may be a combination of various tools, hepa vacuums, pneumatic brushes and air compression to get the desired results for the job.
In the commercial environment it is going to depend upon many factors affecting the building. Is there high usage of the space? What is the space used for? What is the desired level of cleanliness for the space? All of these questions and more should be discussed and a plan can be implemented to best suit the needs for the specific facility.
Some homeowners who are sensitive to their indoor environment have us clean their ductwork annually. Most people should have the ductwork in their home cleaned every three years.
Access: The ability to gain entry to the interior of the air duct or HVAC component.
Access Door: Fabricated metal barrier (hatch) by which a service opening is accessed or closed.
Adhered Substance: A material, such as mastic, that is not removable by direct contact vacuuming.
ACGIH: American Conference of Governmental Industrial Hygienists.
Adhered Particulate: Any material not intended or designed to be present in an HVAC system, and which must be dislodged in order to be removed.
Aerosols: Solid or liquid airborne particles.
AIHA: American Industrial Hygiene Association.
Air Duct: A passageway for distribution and extraction of air, excluding plenums not installed in accordance with SMACNA Standards (SeeASHRAE Terminology of Heating, Ventilation, Air Conditioning & Refrigeration, 1991).
Air Duct Covering: Materials such as insulation and banding used to cover the external surface of a duct.
Air Duct Lining: Generally refers to fiber glass or other matting affixed to the interior surfaces of the air ducts for thermal insulation and noise attenuation.
Air Filtration Device (AFD): A portable or transportable, self-contained blower assembly designed to move a defined volume of air equipped with one or more stages of particulate filtration. Depending on the mode of use, an AFD that filters (usually HEPA) and re-circulates air is referred to as an "air scrubber." One that filters air and creates negative pressure is referred to as a "negative air machine."
Air-handling Unit (AHU): A packaged assembly, usually connected to ductwork, that moves air and may also clean and condition the air.
Coils: Devices inside an HVAC system that temper and/or dehumidify the air handled by the HVAC system. These include heat exchangers with or without extended surfaces through which water, ethylene glycol solution, brine, volatile refrigerant, or steam is circulated for the purpose of total cooling (sensible cooling plus latent cooling) or sensible heating of a forced-circulation air stream
Collection Device: A HEPA-filtered machine designed primarily to collect debris, filter particulate and discharge air back to the indoor environment, or a fan driven non-HEPA-filtered machine that is designed to collect debris, and then filter particulate while discharging the air outside the building envelope.
Ductwork: A system of passageways for distribution and extraction of air, excluding plenums not installed in accordance with SMACNA Standards
EPA: United States Environmental Protection Agency
Duct Access Door: Fabricated metal barrier (hatch) by which a service opening is accessed or closed.
HEPA: High Efficiency Particulate Air. To be called a true HEPA filter, or certified HEPA filter the filter must have a documented filtration efficiency of 99.97% at 0.3 micron-sized particles.
HVAC System: The heating, ventilation, and air conditioning (HVAC) system includes any interior surface of the facility's air distribution system for conditioned spaces and/or occupied zones. This includes the entire heating, air-conditioning, and ventilation system from the points where the air enters the system to the points where the air is discharged from the system.
IAQA: Indoor Air Quality Association
Mold Contaminated: The presence of indoor mold growth and/or mold spores, whose identity, location and amplification are not reflective of a normal fungal ecology for an indoor environment, and which may produce adverse health effects and cause damage to materials, and adversely affect the operation or function of building systems.
Porous HVAC System Surface: Any surface of the HVAC system in contact with the air stream that is capable of penetration by either water or air. Examples include fiber glass duct liner, fiber glass duct board, wood, and concrete.
Thermal Acoustic Materials: HVAC insulation materials designed for sound and temperature control.
UL: Underwriters Laboratories, Inc.
Vacuum Collection Equipment: See "Collection Device."
Visibly Clean: A condition in which the interior surfaces of the HVAC system are free of non-adhered substances and debris.
Visual Inspection: Visual examination with the naked eye of the cleanliness of the HVAC system.
Wet Process Cleaning: Any method of mechanical cleaning of HVAC components that utilizes water and/or liquid chemicals as part of the process (i.e. power washing, steam cleaning, hand washing).
Human Health Concerns, Energy Management and Indoor Environmental concerns will be addressed.
Utility bills can be lowered
Allergy & Asthma sufferers can be helped.
Indoor cleaning can be reduced
Remove unwanted indoor pollutants; mold, fungus, bacteria and mites
Can the company show proof of NADCA membership and certification?
How long has the contractor been in the residential HVAC system cleaning business?
Can the contractor provide you with evidence of the current Worker’s Compensation and General Liability Insurance coverage? (Ask for Certificate of Insurance)
Does the contractor posses the proper Licenses that are required by your city or state to perform the work they are proposing? (Not all cities or states require licenses - click here to check your state.)
Can the contractor provide you with 3 to 5 customer references with phone numbers for projects of similar size and scope of work which they provided service in the last year?
Does the contractor have written safety, respiratory, and confined space programs in addition to OSHA compliance reports?
Will the contractor provide you with a means to conduct a visual inspection at any time during the cleaning? (Mirror and flashlight, camera or other remote visual systems)
Will the contracting company actually do the work? (Some companies subcontract the work to independent contractors. You will want to apply these guidelines for subcontractors as well.)
• Can the company show proof of NADCA membership and certification?
• Will the contractor conduct a thorough inspection of your system PRIOR to performing any work and alert you to any problems? This is required by the current NADCA ACR Standard.
• Is the HVAC system fully operational prior to cleaning?
• I Clean Supply Ductwork
• I Clean Return Air Ductwork
For Metal Ductwork:
Q: Are interior ductwork surfaces free of visible debris? (Select several sites at random in both the return and supply sides of the system.)
For Fiberglass, or Fiber-lined, Ductwork or Ductboard:
Q: Is all fiberglass or lining material in good condition (i.e., free of tears and abrasions; well adhered to the interior of the duct)
• Remove, Clean and Reset:
- Supply Registers
- Return Air Grilles
Q: Are the registers, grilles, and diffusers visibly clean?
Q: Are all the registers, grilles, and diffusers properly reset?
• Access and Clean:
- Supply Air Plenum
- Return Air Plenum
Q: Is the supply plenum (directly downstream of the air handling unit) free of moisture stains and contaminants?
Q: Is the return air plenum free of visible dust and debris?
• Install Access Panels as Needed
Q: Are access panels properly sealed according to the NADCA ACR Standard?
• Clean Airstream Side of Heat Exchanger
Clean Secondary Heat Exchanger
Q: Was proper access made to the heat exchanger?
• Remove, Clean and Reinstall
- Blower Motor, Housing & Assembly
Q: Are the blower blades clean and free of oil and debris?
Q: Is the blower compartment free of visible dust and debris?
• Clean Evaporator Coil, Drain and Pan *
Q: Which cleaning method was used?
Type 1: Contact vacuum, brush, or air wash
Type 2: Use coil cleaning chemicals and water
Q: Are both sides of the cooling coil visibly clean?
Q: If you point a flashlight into the cooling coil, does light shine through? It should if the coil is clean.
Q: Are the coil fins straight and evenly spaced (as opposed to being bent over and smashed together).
Q: Is the coil drain pan clean and draining properly?
• Replace air filter
Q: Do filters fit properly and are they the proper efficiency as recommended by the HVAC system manufacturer?
• Wash air cleaner-
If no to any of the services listed above, why not?