Your customer has a problem. S/he can’t find the source of what is making him/her sick. So you don your professional jacket and diagnose the problem. Better yet, you offer a remedy, too.

No, this isn’t a scene from “General Hospital,” it is a common scene for HVAC contractors who are being called on to solve their customers’ indoor air quality (IAQ) problems.

Building and home occupants are getting ill due to a variety of factors, including building construction, lack of HVAC system maintenance, cleaning products, pets, cooking, synthetic products in furnishings, etc.

The News will examine some of these sources and products necessary to combat poor IAQ.

GeneralAire's AC-1 residential air cleaner has 78 square feet of microfiber filter media. (Photo courtesy of General Filters Inc.)


“The real surge in IAQ problems, the consequences of which we are still experiencing, can be traced directly back to the tight residential construction policies which resulted from the 1973 oil embargo,” said Rick Stoltz, director of Integrated Marketing for Skuttle Indoor Air Quality Products, Marietta, OH.

“At the time, it seemed clear that tighter homes and more efficient heating and cooling systems would help guard against future energy crises,” he said, “and so they did. But the unforeseen results are homes that don’t breathe, poor indoor air quality, and an increase in asthma, allergies, respiratory illnesses, and in-home suffocation. Statistics reveal that it is the tight homes, built since the late 1970s, that have the highest incidences of IAQ-related ailments.”

Stoltz cited humidity as one cause of poor IAQ. “Too much or too little humidity in a home promotes an increase in bacteria, viruses, fungi, mites, respiratory infections, allergic rhinitis and asthma, chemical interactions, and ozone production.”

One expert said it isn’t easy to lay the blame on any one particular source. “When you look at all of the potential IAQ problems, from asbestos to mold to formaldehyde to environmental tobacco smoke and so on, I don’t know that we can pinpoint any one problem as the main contributor to IAQ problems,” said Dave Shaggot, president of Abatement Technologies Inc., Duluth, GA. “The scientific community has determined that most IAQ problems involve multiple sources, including those referenced above.

GeneralAire's AC-3 combination unit includes both the AC-1 air cleaner and AC-2 air purifier. (Photo courtesy of General Filters Inc.)

“Most often the synergistic effect of these sources magnifies the problem. In other words, IAQ problems are one area where one plus one might equal four in terms of the severity of the effects on humans. Consider mold, for example. A study conducted by the Mayo Clinic in 1999 found that fungi (molds) were present in 96% of the chronic sinusitis patients they studied. Molds require three main conditions to survive: a food source such as dirt or sheetrock, moisture, and a surface to grow on.”

Greg Steiger, marketing manager for Trion Inc., Sanford, NC, said that “Poor IAQ is caused by pollution within the building. Sources of pollution include cleaning agents, upholstery, copy machines, carpeting, printers, pollen, viruses, bacteria, and mold. All of these pollutants are trapped within buildings without air-cleaning equipment and proper ventilation.”

One expert said that many homes look the same but the similarity ends with the construction materials — thus the dissimilarity of IAQ in seemingly identical living spaces.

“There are too many houses built exactly alike and most don’t have a problem, while a few do,” said Jerry Wolf of Air Purification Systems, Houston, TX. “Now there might be an exception such as stucco on the outside that leaks, or maybe something like the extensive use of fiberboard in the ductwork that may harbor mold better than other products.

“I’m from the old school and when I recently built a new home I put in metal duct, insulated on the outside. You don’t see that real often anymore.”

Dynamic Panels from Environmental Dynamics Group can retrofit into residential and commercial HVAC systems to provide high-efficiency air cleaning. (Photo courtesy of Environmental Dynamics Group.)


Duke Wiser of Environmental Dynamics Group, Princeton, NJ, said that a variety of products are available to fight poor IAQ.

“Because IAQ problems are usually due to a combination of contaminants, it is important to be able to address the three basic categories: particle, biological, and gas phase,” Wiser said. “Our systems are designed to do just that. Our Panel Air Cleaners capture particles (including those in the dangerous submicron range, such as smoke and dust damaging to lungs), biologicals such as mold spores, bacteria, and viruses, and will significantly reduce harmful gas-phase contaminants such as formaldehyde.

“Our germicidal systems are used in applications where biological control is critical and combine high-output UVC in patented configurations that scan and penetrate our sparse media. This ensures the proximity and contact time necessary for UVC to inactivate the collected pathogens,” he said. “Operationally, our systems increase in efficiency with use and can, in many cases, reduce overall system static.”

Stoltz said that his company, Skuttle, addresses three important areas of IAQ: humidification, filtration, and ventilation. “Skuttle humidifiers restore a home’s relative humidity to a balanced, healthier, more comfortable 30% to 50% range, which minimizes high or low humidity conditions.

“Our duct-mounted air cleaners capture most of these contaminants in a deep-pleated filter, which traps far more particulates over a longer period than standard, flat-filter designs,” he said. “The results are cleaner indoor air, a cleaner HVAC system, longer filter life, longer furnace life, and a healthier living environment.

“To help eliminate airflow problems, Skuttle manufactures two ventilation products: the makeup air diffuser, which supplies additional combustion air to appliances that have inadequate combustible air sources; and the Model 216 makeup air control, which reduces unwanted air infiltration by drawing outside air into the furnace, where it is filtered, heated or cooled, and circulated through the home’s duct system. The slight pressure buildup keeps untreated air from seeping in around windows and doors.”

General Filters Inc., Novi, MI, offers a selection of GeneralAire IAQ products, in addition to an interactive website ( Lou Laroche, General Filters’ national sales manager, said that the company’s IAQ products include:

  • Flow-through humidifiers — A portion of the heated air from the furnace passes through a water-soaked pad, where it absorbs additional moisture and then returns for distribution throughout the home.

  • Reservoir (drum-type) humidifiers — Heated air passes through a water-laden evaporator sleeve, absorbs moisture, then returns to the heating system for distribution throughout the home.

  • Duct-mount humidifiers — The model fits all forced-air heating systems, including heat pumps, and mounts horizontally in the warm-air duct. The water-soaked, rotating drum has a large surface area for maximum absorption.

  • Air cleaners — The company says its AC-1 removes pollen, mold, dust, animal dander, grease, soot, and tobacco smoke for cleaner, fresher air.

  • Air purifiers — More than 4 pounds of activated carbon pellets are designed to remove noxious fumes, vapors, and gases circulating indoors. Low pressure drop design does not interfere with proper operation of the heating-cooling system, the company says.

    The patented Sterile Sweep system couples a high-output UVC lamp with an oscillating parabolic reflector designed to inactivate airborne pathogens. (Photo courtesy of Environmental Dynamics Group.)
    “Our main products are high-efficiency air purification equipment designed for specific IAQ remediation applications and sold under the HEPA-Aire trademark,” said Abatement Technologies’ Shaggot. “Most of these products are equipped with true HEPA [high-efficiency particulate air] filters certified to a minimum efficiency of 99.97% to 99.99% at 0.3-micron particle sizes.

    “These products include portable equipment for residential and commercial air duct cleaning; HVAC-mounted central air-purification systems for residential, commercial, and healthcare facilities; portable air scrubbers for mold remediation and fire and water damage restoration; and negative air machines and other products for asbestos abatement.

    “Other technologies incorporated into some of our products include germicidal UVC irradiation and photolysis/oxidation for enhanced effectiveness against microbial contaminants, and carbon adsorption for capturing gases and odors.”

    Collection systems are a specialty of Trion. “The Fedders Indoor Air Quality Group improves IAQ through the sale of Trion dust-collection systems, oil mist-collection systems, media filters, electrostatic air cleaners, Envirco fan filter units utilizing HEPA and ULPA filters, and Herrmidifier humidification equipment,” said Trion’s Steiger.


    Shaggot related how an HVAC contractor “came to the rescue” of a homeowner with a serious IAQ problem.

    “One recent case study that specifically comes to mind is a home in Atlanta [GA] that had a variety of IAQ problems,” Shaggot said. “These problems were exacerbated by mold infestation following a flood.

    “The residents, who were already being treated by a local allergist for severe allergy and asthma problems, actually had to abandon the home once the mold problem was discovered and the family’s health worsened.

    “The insurance company involved became desperate because it appeared that the home might possibly become a total loss unless the causes of the IAQ problems could be eliminated. They contacted a contractor who ultimately solved the problems using a variety of IAQ-remediation techniques, including source removal air duct cleaning (using our equipment), duct sealing, air balancing, and the introduction of fresh air. The contractor used Abatement Technologies’ CAP1200 Central Air Purification system.”

    Publication date: 07/22/2002