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 Survey Digs Out the Dirt on HVAC Coil Cleaning


Nicotine, mold and soot clog a coil in Michigan.

It seemed like an odd place to raise the issue. The Associate Council meeting at the National Air Duct Cleaners Association convention is where the HVAC system cleaning industry’s manufacturers gather once a year to hear about new NADCA programs for vendor members and to share ideas to help forward the mission of the association. That’s where Tom Yacobellis first chose to publicly challenge NADCA on whether its members comply with the association’s obligatory standards.

Yacobellis spent almost a decade on the NADCA Board of Directors and remains one of the association’s most active volunteers. He belongs to NADCA’s standards and certification committees, and he conducts the bulk of the association’s Air System Cleaning Specialist exam preparatory class. Yacobellis is also president of Buster Enterprises, a franchiser whose Ductbusters network extends to 30 offices across the globe.

Click on the graphs to enlarge.

At the Associate Council meeting, Yacobellis revealed that Buster Enterprises, as part of its regular investigations into market trends in areas it services, had discovered that a large number of contractors – both members and non-members of NADCA – do not offer coil cleaning as part of their regular service package. “NADCA standards require total system cleaning, not just duct cleaning,” Yacobellis remarked. “As vendors of equipment and services, we need to know whether or not NADCA is going to enforce this standard.”

At first, the Associate Council chair tried to deflect Yacobellis’ line of questioning by suggesting he instead raise the issue with the NADCA staff and elected board members. “I have spoken to NADCA’s executive staff and other association officials about this several times,” Yacobellis countered. “I never get an answer and, to be honest, it’s getting really frustrating.”

A member of the NADCA board who was co-chairing the Associate Council meeting suggested that if Yacobellis was so passionately concerned about the issue, he should select a more appropriate forum in which to raise it – namely, the following day’s NADCA General Membership meeting. “Actually, this was just a dry run for tomorrow,” Yacobellis quipped. But he wasn’t joking.

“Complete” System Cleaning?

The term “duct cleaning” is widely used to describe the work performed by companies that clean HVAC systems. NADCA says the term “duct cleaning” is a misnomer because it implies that only ductwork is cleaned. According to NADCA documents, “HVAC system cleaning” is a more accurate description of the work performed by its members. In fact, NADCA advocates that all HVAC systems receiving cleaning service undergo complete cleaning of all system components.

There is a section on the NADCA Web site providing consumers with a post-cleaning checklist. Among the items they are told to verify is that the service provider obtained access to and cleaned “the entire heating and cooling system, including duct work and all components (drain pans, humidifiers, coils, and fans).” Consumers are also told to verify that “both sides of the cooling coil [are] visibly clean.”

As a condition of membership, NADCA members are obligated to follow NADCA Standard ACR 2002, “Assessment, Cleaning and Restoration of HVAC Systems,” which is specific in defining coils and air handling units as a portion of the HVAC system requiring cleaning for a job to be in compliance with the standard. “All portions of the coil assembly must be cleaned. Both upstream and downstream sides of each coil shall be accessed for cleaning,” the standard says.

The U.S. Environmental Protection Agency’s consumer guidance on HVAC system cleaning parallels that of NADCA. “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,” the agency advises, also recommending that consumers select contractors who comply with NADCA standards. Like NADCA, the EPA recommends that after cleaning the consumer should verify that all system components were cleaned. In fact, the EPA and NADCA post-cleaning checklists are nearly identical.

If you ask an IAQ investigator what part of the HVAC system typically harbors microbial contamination, “the coil and drain pan” will be the response almost every time. They are excellent collection points for small particles of dust that pass by or through the HVAC filter. They are moist and temperate.

The EPA’s position on mold in HVAC systems is surprisingly strong. “Do not run the HVAC system if you know or suspect that it is contaminated with mold,” says the EPA publication “Mold Remediation in Schools and Commercial Buildings.”

Coils are a breeding ground for mold. Everyone agrees on that point. Given that reality, one would think cleaning coils and interior surfaces of air handling equipment would be high on list of services offered by the cleaning industry. Think again.

The Horse Wouldn’t Drink

We all know the old saying: You can lead a horse to water but you can’t make it drink. At the NADCA convention in New Mexico, Tom Yacobellis led the entire corral to water. They weren’t thirsty.

During the NADCA General Membership meeting, a wide range of controversial issues came forward about the association and how it conducts its business. By the time Yacobellis made his way to the microphone, there was already a sense of vigilantism in the air.

Yacobellis laid out his concerns concisely. He pointed out that everyone in the room knows the area of the system most likely to grow mold is the coil. He explained that his organization has conducted several surveys over the years and found that many, many contractors don’t clean coils, including NADCA members. “If you don’t clean coils, I think you’re missing something, but I’m not up here today to get you to change. What I want is for NADCA to stop misleading consumers,” Yacobellis said.

During his comments, many of the more than 400 people in the room nodded in agreement. But the support seemed somewhat tentative. An observer in the room couldn’t help but wonder how many of the people present don’t clean coils. The answer seemed apparent a moment later when Yacobellis made a motion.

“I move that the NADCA Web site be changed to add a disclaimer advising the consumer that not all NADCA members perform complete system cleaning that includes all components,” Yacobellis stated. His motion was seconded, discussed, and called for a vote. It was rejected by at least two-thirds of the membership.

IEC Uncovers What’s Really Going On

What we heard at the NADCA convention made IE Connections staff curious. Was Yacobellis right? Was a sizable percentage of the HVAC system cleaning industry failing to clean coils? Are NADCA standards really being upheld?

We developed a list of questions we wanted to know about HVAC cleaning contractors. Of course we wanted to know if they cleaned coils. We also wanted to know what basic methods of cleaning they use, if they follow containment protocols and whether they offered sanitizers. Other items on our questionnaire included length of job, price, and whether or not a price would be quoted before a pre-inspection. Every single company we spoke with quoted a price by phone.

Posing as consumers shopping for cleaning services, our staff interviewed 36 duct cleaners across six geographical areas. Our survey results include responses from these 36 companies. Half of those surveyed in each area are NADCA members. The NADCA members were selected from lists generated off the member listings of the NADCA Web site. Non-members of NADCA were found in listings at superpages.com or yellowpages.com.

Several experts agreed with our estimation that the HVAC system cleaning industry is comprised of approximately 5,000 companies. Given the size of the industry’s population, our survey has an error level of plus or minus 13.5 percent and a 90 percent confidence rating. In other words, if we were to conduct the same survey 100 times, the results would be within plus or minus 13.5 percent of the first time we ran the survey 90 times out of 100.

Data were collected in the following manner. All companies were told the caller is suffering terribly from allergies this season and his or her allergist suggested getting the air conditioning system cleaned might help. Companies belonging to NADCA were also told that the caller learned about the company from the NADCA Web site.

After this introduction, the caller asked the company representative to describe the cleaning services available. During the description, the caller recorded information on our checklist of questions. Questions not answered during the initial presentation were posed in a series of follow-up questions during the call.

More than 60 companies were called in order to reach 36 who had a live representative available to discuss his or her company’s services. Data was collected only on those companies that were available for the complete telephone interview.

After data were entered into a spreadsheet for interpretation, statistical analysis was performed to identify any anomalies in the data. Whenever significant anomalies were discovered, follow-up calls were made to confirm that the data originally collected was accurate. None of our original data required correction as a result of secondary confirmation phone calls.

The companies we surveyed all provide HVAC cleaning services; however, they have their roots in a wide range of industries. Only 36 percent of the companies we surveyed were primarily in the business of HVAC system cleaning. The others included HVAC mechanical contractors, carpet cleaners, chimney sweeps, restoration firms and construction firms.

Survey Results

Of the companies we surveyed, 58.3 percent did not mention coil cleaning when asked to describe their services and prices. When asked whether coil cleaning was included in their services, they said no. When subsequently asked if coil cleaning was available, half of these companies said the service could be provided at an additional fee. Thirty percent of the companies surveyed do not offer coil cleaning at all.

A significantly higher percentage of NADCA members offered coil cleaning than non-members, with 61.1 percent of them including coil cleaning in their initial description of services and price quote. Only 22.2 percent of non-NADCA members offered coil cleaning in their initial descriptions.

Eleven percent of the companies we spoke to proposed replacing the coil rather than cleaning it. All were HVAC contractors. Of this group, 75 percent also said replacing the entire furnace was probably the best alterative to improve IAQ. Our callers had described their HVAC systems as less than 10 years old and in seemingly good mechanical condition.

These findings appear to vindicate Yacobellis’ convictions. Indeed, despite the fact that we disclosed we found the company’s name through NADCA and that our inquiry was based on a recommendation from an allergist, 38.9 percent of NADCA members (and 77.8 percent of non-NADCA members) offered a service that did not include cleaning the HVAC coil.

Based on our survey, we find that a high number of “duct cleaners” do just that – clean ducts, not the complete HVAC system. Given the knowledge that mold contamination is commonly found growing on and within HVAC system coils, and given EPA’s recommendation that consumers not run HVAC systems if they are known or suspected to harbor mold, the fact that so many contractors would be willing to offer a cleaning service that completely omits the coil is hard to comprehend.

One of the items we were interested to learn about was how widely antimicrobial sanitizers are used in the HVAC cleaning industry. Our results show 69.4 percent of companies offering sanitizer application; 72.2 percent of NADCA members and 61.1 percent of non-NADCA members automatically included the sanitizer in their service description and price. Of the entire population surveyed, 13.8 percent said they could not say if a sanitizer would be needed until they had inspected the HVAC system, while 22.2 percent of the survey group did not offer sanitizers as part of their service.

Our questionnaire was also designed to determine if the companies used large negative air machines or “power vacs” to place the system under negative pressure during cleaning. This is an essential containment requirement of NADCA Standard ACR 2002. One hundred percent of NADCA members responded in the affirmative. Of non-NADCA members, 22.2 percent provide a cleaning method that does not include a large negative air machine or power vacuum. All of these companies are carpet cleaners.

The fact that non-NADCA members compared poorly to NADCA members did not come as a surprise. NADCA members invest heavily in obligatory training and certification and they are bound by an enforceable code of ethics. When we spoke to the non-NADCA members, we asked them if they belonged to NADCA, and 22.2 percent said “yes” but were not truthful.

Our survey included job completion time. We described our home as a mid-sized two-story (no basement), three-bedroom residence with an HVAC mechanical room on the first floor. Because some companies send only one service technician whereas others send two or three, our figures are presented in man-hours per job rather than in job completion time. The average number of man-hours required by a NADCA member was 8.72, whereas the average non-NADCA member said they could complete the job in 6.05 man-hours. The fastest contractors were two carpet cleaners who both said they could get the job done with one man in two hours. These were also the lowest priced contractors, and neither offered coil cleaning.

They say you get what you pay for, but that doesn’t appear to hold true in HVAC cleaning. While the NADCA members had stronger responses to our questionnaire overall, the average price quoted by a NADCA member was $424.55, compared to an average price of $431.66 among the non-NADCA members. The range of prices quoted by NADCA members spans from a low of $240 to a high of $785. Among non-NADCA members, the range is $195–$710.

The survey conducted by Indoor Environment Communications for this project generated a great deal of additional data that have been statistically analyzed from a variety of perspectives. The complete survey results and analysis report are available for a fee. For a prospectus, contact Steve Sauer by e-mail at IECnews@aol.com or by phone at (301) 230-9606 ext. 17.

This article appears in Volume 5, Issue 7 (May 2004) of Indoor Environment Connections newspaper and is reprinted with permission of Indoor Environment Communications. For subscription information, visit www.ieconnections.com.


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