Tips on Controlling Humidity Levels (and Mold)
July 18, 2011
Back in the early 2000s, it was “sexy” to talk about black mold and its notoriety because of high profile cases involving the likes of Ed McMahon and the $32 million awarded to a Texas family whose home was overrun in 2001 with stachybotrys mold spores. (Visit The NEWS’ archives for more information: http://bit.ly/meGo9U.)
A lot of litigation has passed through the legal system since then and insurance policies have been reworded and revised to include (or exclude) liabilities for mold damages. “It looks like the insurance companies have worded their mold exclusion clauses in commercial policies to remove their liability, and therefore there is less money available to plaintiffs if they prevail in a legal action,” said Gregg Burnett CEO of Dust Free, LP.
But the problems shed new light on the root cause of mold growth: excessive moisture from water or high humidity levels, which create a breeding ground for mold growth. It seemed that the good idea of sealing up a building to make it energy efficient had some unwanted side-effects. Lack of circulation or the inability for a building to breathe compounded the high humidity problem.
“Dirty, damp ductwork and wet, scummy drain pans can breed micro-organisms that become airborne which gets into the air we breathe,” said Lon Cassel, vice president of the Consumer Products Division of Clockwork Home Services. “Any place there is standing stale water or damp walls from roof leaks or condensation can also cause growth that is injurious to our health.”
Fortunately, the HVAC trade has remained a leader in providing information, answers, and products to combat the humidity problem.
“Humidity control is essential to providing healthy IAQ,” said Ken Forsythe, marketing product manager CertainTeed’s Mechanical and Industrial Insulation Group. “Moisture can create an atmosphere environment that is ripe for the growth and generation of bio-aerosols such as bio-organisms and mold.
“This can cause serious health issues for building occupants, as well as lead to Sick Building Syndrome (SBS), a condition where a building’s IAQ hits such low levels that the intended use of the building becomes impaired or impossible.”
Burnett said, “Once dormant mold spores within the envelope receive enough moisture to grow, the mycotoxins that mold colonies produce can be inhaled by the building occupants.”
Moisture can build in a number of different places within a building envelope, but particularly on uninsulated sheet metal ductwork. According to Forsythe, this moisture often arises from condensation that forms on the inside and outside of HVAC ductwork and is caused by the changing temperatures of different seasons. During the summer, as cold air travels through warm, uninsulated ducts it causes beads of moisture to form on the interior or exterior of the ducts. And, during winter, heated air does the same as it travels through cold ducts.
“Condensation will occur on any duct surface where the temperature is either equal to, or lower than, the dew point temperature,” he said. “The IAQ concerns begin, however, when this condensed moisture mixes with dust or dirt present in uninsulated ducts to foster mold and microbial growth, which, in turn, can pollute the air supply of the building. If the condensation is left untreated, this mold and microbial growth will continue to worsen, leading to contaminated interior air.”
Forsythe added that HVAC systems have often been referred to as the “lungs of a building” because they essentially do the structure’s breathing; they ventilate stale or contaminated air from a space and replace it with fresh conditioned air, similar to the inhaling and exhaling functions of lungs. “As with lungs, it’s important to keep the inside of the HVAC system’s ductwork clean and free of impurities,” he said. “The HVAC system is responsible for distributing air throughout the whole building, so any impurities, such as mold and microbial growth, found in the ductwork will be infused into the interior air the occupants breathe.”
SOLUTIONS TO CONTROL MOLD GROWTH“The proper methods of duct source removal, coating coils with anti-bacterials, and condensate pan treatments strips are all cost effective ways to remove and prevent these problem areas from causing IAQ challenges,” said Cassel. “Proper humidity levels should also be maintained to prevent mold growth and other musty moisture problems.”
Forsythe said that some thought and planning should go into any measures to prevent mold growth. “Fortunately, building and design professionals can avoid these IAQ threats with some proactive planning,” he said. “One important tactic for mold prevention is lining the ductwork of a building’s HVAC system with fiberglass insulation. HVAC ductwork is a target area for mold growth that doesn’t always receive enough attention, despite its importance to the occupants of a building.
“Well-insulated duct systems can help prevent mold growth by maintaining a constant temperature in the ductwork, significantly lowering the possibility of condensation on duct surfaces and protecting against microbial growth. According to the North American Insulation Manufacturers Association, fiberglass insulation does not support mold growth or act as nutrients for mold growth. Fiberglass duct liners are also resistant to microbial attack.”
Burnett said a key to controlling humidity levels is the condition of the coil. “The more efficiently the cooling coil operates, the more humidity can be removed from the air,” he said.
Cassel said that controlling humidity levels may be good for healthy IAQ, but then again, there may be bigger issues. “Regular system maintenance has more of a positive effect on the performance of the equipment than it does on cleaner, fresher, and healthier air,” he said. “Keeping the outside coil, inside coil, and blower wheel clean will keep it running at factory fresh conditions and could add up to as much as 30 percent savings on your energy bill.
“Checking for and removing any other growth and dust inside the system can help with indoor air quality concerns, however improved filtration and the use of high output dual wavelength UV lights will give you substantial results of keeping the system cleaner between maintenance visits and substantially reduce particles, germs and gases that aggravate allergies, asthma and other ailments.”
Products available from sources quoted in this article include:
CertainTeed – ToughGard® T Textile Duct Liner is an acoustical liner for HVAC sheet metal ducts, improving the energy efficiency of an HVAC system by reducing heat gain or loss and minimizing moisture problems due to condensation.
CertainTeed – SoftTouch™ Duct Wrap Insulation is a resilient blanket insulation composed of glass fibers bonded together with thermosetting resin that is easily fit and installed on HVAC ductwork.
CertainTeed – WideWrap Duct Wrap is a new fiberglass duct wrap product that provides superior condensation control, and comes in a 5-foot width.
Dust Free – Bio-Fighter UVC lights, which can significantly reduce the presence of bio-film on cooling coils.
Clockwork (Nature’s Home) – MicroPower Guard® which is a polarized-media electronic air cleaner.
Clockwork (Nature’s Home) – OxyQuantum® LED is a dual lamp system combining UVC and UVV to reduce and control odors, toxic compounds, and infectious agents.
IS IT A NICHE?Promoting healthy IAQ is a natural part of selling HVAC equipment - it goes hand-in-hand. But is there a separate niche that HVAC contractors can pursue outside of the add-on potential to selling a replacement air conditioner or furnace? Absolutely.
“It would certainly be to the advantage of any HVAC contractor to develop an expertise concerning IAQ,” Forsythe said. “Pick up any related magazine, such as The NEWS, and you will see articles about how to improve IAQ. There is a high demand for healthy buildings and the contractors who understand the challenges, and know the best solutions will be best poised to win the business for projects where IAQ is a priority.”
Burnett said, “The HVAC contractor is selling a large portion of what makes an environment comfortable - the air component. The overall quality, or comfort of the air, is affected by the levels of temperature, humidity, particulate, volatile organic compounds (VOCs), and microbials. Providing technology that keeps all of these metrics at comfortable levels is something that most North American consumers will place a value on.”
That technology is something that can be learned on the job or through training and education. Cassel said that Clockwork is poised to make HVAC contractors successful in the IAQ business. “We offer weekly web training for technicians, managers, sales staff, and installers,” he said. “We also offer onsite training on a monthly basis. Training, then holding them accountable and then motivating are keys to increase indoor air quality revenue. Employees have to believe in the technology and be able to transfer this belief to the homeowner.”
Mark Atherstone, Goettl’s residential customer relations manager, said that in order to add IAQ products to a market mix, the first place to start is education, but not just product training. He said that only 20-30 percent of IAQ training should be focused on specific products.
“Product training alone will not place the product in the home,” he said. “Technicians and advisors need to understand the problems and effects of poor air quality. When team members are not confident about the benefits IAQ products provide the homeowner, they are uncomfortable offering IAQ solutions and options to the client.
“When a company is ready to increase its IAQ revenue, it is important that everyone who has the opportunity to offer IAQ products to the client receive proper training. And this includes not just advisors and service technicians, but also installation technicians and office personnel that interact with clients.”
Publication date: 07/18/2011