When building service contractors address customer needs, they should make sure not to overlook air-duct cleaning. While an office space or complex might seem clean on the surface, built-up soil and dirt can continue to circulate via the heating, ventilating and cooling (HVAC) systems that serve the entire building.

Contractors who want to provide a full range of solutions to their customers would do well to ally with a reputable HVAC cleaning service to provide air duct cleaning. But there are a few things BSCs should know before calling in experts, to make sure they answer customer questions properly and choose the right contractor as their partner.

First, the term most commonly applied to HVAC work is air-duct cleaning, but this actually is a misnomer. To ensure that the air in the commercial space served by an HVAC system is clean, the entire system needs service. This includes the air- handling unit, all return and supply ductwork and registers, fans and fan housings, coils, filters and filter housings, mixing boxes, turning vanes, dampers and condensate drain pans. If only the ductwork is cleaned, there is a highly likelihood that cross-contamination will occur.

The cleaning process involves the removal of contaminants from the entire HVAC system. Contaminants may include dirt, dust, construction debris, bacteria, fungi (mold and mildew) and animal dander. To remove these contaminants, the contractor should follow effective source- removal methods involving special forced air and mechanical brushes to agitate built-up dirt and debris. Vacuum systems with HEPA filters then help remove the contaminants.

The cost of properly performing these services for a commercial system varies greatly depending on the size of the facility, the number of HVAC systems, the current or past use of the facility and the facility’s age. As a gauge, contractors can note that a typical one-unit, residential project could cost between $400 and $700.

The National Air Duct Cleaners Association (NADCA) also recommends that HVAC systems receive routine visual inspections to determine cleanliness, since each facility will accumulate build-up at different rates, based on the activity in the building and the HVAC systems operations. The air-handling unit also should be inspected at least annually. If the air-handling unit inspection reveals contamination, then the supply and return ductwork should be inspected at that time.

According to NADCA’s latest standard, ACR-2002, if significant accumulations of contaminants or debris are observed within the HVAC system, then cleaning is necessary. Likewise, visible evidence of microbial growth or other indications of such contamination found throughout the building require immediate attention.

Indoor air quality (IAQ) and mold are two related hot topics in the HVAC industry right now. HVAC cleaning not only helps reduce visible dirt accumulation, but it also helps prevent the circulation of dust and bacteria that can cause a variety of health problems throughout a building.

At the moment, one concern is mold growth because certain strains can cause health problems under the right conditions. Cleaning systems that have mold growth requires special containment and remediation procedures to ensure that no cross-contamination occurs throughout the building during the procedure; the mold is completely removed;the source of the moisture that is allowing the mold to grow is halted; and that the HVAC system is not damaged during the remediation process. Because this process is so complex, special training and certification is vital and BSCs should be extremely cautious in their choice of HVAC partners.

Before calling to inquire about a company, BSCs should visit the NADCA Web site, www.nadca.com, to check out the Consumer Information section. This area contains answers to frequently asked questions, as well as some basic information about duct cleaning procedures. By educating themselves about the process, contractors will be better prepared to ask the right questions.

Another easy way to find a reputable company is by calling NADCA headquarters for a list of member companies in the area. NADCA offers both training and an Air Systems Cleaning Specialist certification (ACSA) program. Member companies of NADCA are required to have at least one individual on staff that has taken and passed this exam. They also must clean according to NADCA standards.

Many companies claim they are air-duct cleaners, but use inadequate equipment or do low-quality work. As part of the membership agreement, NADCA companies pledge to follow the associations standards or risk an investigation into their practices. Should a BSC or their customer be dissatisfied with an HVAC job, they can call the association and file a complaint. NADCA then acts as a consumer advocate, investigating the claim and bringing the company in question before its ethics committee.

To receive more information regarding HVAC cleaning or the NADCA, call 202-737-2926.

Terry Bray is a partner of Air-Vent Duct Cleaning Inc. of Ambler, Pa. and Hammonton, N.J., who serves on the NADCA board of directors.

Jesse Madden is the director of publicaions for NADCA and can be reached at 202-737-2926.