Rick Tullis, president, Capstone Mechanical, Waco, Texas, said contractors should be aware of the factors that limit mold’s ability to multiply throughout an indoor environment.

“We are surrounded by many types of molds and microbes, no matter how clean we keep our homes. Our best hope is to limit the growth of the mold and prevent it from setting up an active colony,” he said. “To do that, we need to do what any good military siege strategist would recommend, prevent the enemy, in our case mold, from getting the food and water it needs to flourish.”

Tullis suggested contractors consider recommending an effective filtration process during HVAC installation, to limit airborne dust that commonly serves as a food source for mold. “Those sources of food can be controlled; however other food sources may be more difficult. In one case, a homeowner’s mold problem was due to their antique book collection and there wasn’t a good solution other than remove the books from the home,” he said.

Speaking from experience, Tullis encourages contractors to examine plumbing and roof leaks, as well as air moisture.

“In my own house, it took hard rain with strong southerly winds to expose a poor flashing installation from my roof when the house was built four years ago. I discovered the problem a few weeks later, as I found mold growing on the ceiling of the guest bedroom closet,” he said.

“Additionally, a poorly installed, designed, or maintained mechanical system may offer a host of potential moisture pitfalls including gaps in piping insulation that may allow condensation on the suction line, low discharge air temperatures, cracked drain pans, poorly insulated plenums, poorly glued condensate lines, unlevel units, and clogged drains.”

Contractors, such as Pat Beyer, owner, Beyer Boys, San Antonio, said that while the primary function of an air conditioner is to cool a home, it may also serve as a moisture eliminator.

“The ability for an air conditioner to remove moisture is especially important in humid areas,” he said. “When moisture is removed, a large amount of condensation is formed. Under normal conditions, the condensate drain carries the water away without an issue. However, clogs can cause detrimental moisture damage in a home.”

To alleviate these potential clogs, Beyer said contractors should encourage annual inspections, algaecide treatments, replacement air filters, emergency drain examinations, the installation of a safety float switch, and more.”

Shaun Mitchell, founder and CEO, Modern Mechanical, Ashburn, Va., said an air conditioner may be an effective tool in the war against mold.

When replacing an existing system, Mitchell encourages customers to install a properly sized, high-efficiency unit with a SEER above 14, which he shares will save energy, money, and more effectively remove humidity from an indoor environment.

“A contractor must properly size an air conditioning unit to match the cooling load in a home. Oversized units cycle on and off frequently, reducing the efficiency of humidity extraction, which leads to other problems. The unit must operate for at least three continuous minutes before the moisture-control function optimizes.”

Mitchell also said homeowners should be taught the difference between operating a unit using the “auto” and “on” switches.

“The ‘auto’ position allows a blower fan to stop intermittently, allowing time for humidity condensed out of the air to drain off the coils,” he said. “When a unit is set to the ‘on’ position, the fan continuously operates, and may evaporate some of the condensation and re-circulate it back into a living space.”

Stan Zywicki, product management leader, indoor air quality, zoning, water with Honeywell International said there are two approaches to combating mold — you can kill it or change its potential living environment to eliminate growing conditions.

“Honeywell’s TrueClean is an example of a product that tries to prevent mold from spreading, and helps reduce issues that may arise from airborne mold spores. Mold spores typically fall in the 3.0- to 10.0-micron range, and TrueClean captures about 98 percent of the particles in this size category passing through the filter, based on ASHRAE 52.2 efficiency testing,” he said. “The other way to combat mold is to prevent it from growing in the first place. The best way to do this is to control humidity in the house. Honeywell’s third-generation of TrueDry dehumidifiers offer many advantages including e-coated coils, quiet operation, reduced vibration, Energy Star ratings, flexible installation options, and more.”

Improved efficiency of HVAC equipment is also intensifying the need for humidity control. As homes are built tighter, natural ventilation and air leakage is reduced, which increases the need for additional ventilation and air movement to maintain healthy IAQ. “Regardless of climate, all facilities are prone to mold growth if preventative measures are not put into place. One simple way to control this unwelcome growth is by introducing air movement into the environment before mold has a chance to flourish,” said Christian Taber, senior applications engineer at the Big Ass Fans Co. “For mold growth to occur, all of the following must be present: appropriate temperature range, mold spores, a food source, and moisture. Removing any one of those four traits eliminates the issue. By adding air movement to the environment, the moisture content and temperature are equalized, dramatically reducing the likelihood of mold occurring.”

Controlling Air Moisture

Humidification and dehumidification issues exist in nearly every indoor environment. Newly developed systems allow contractors to offer a whole-house solution, tackling temperature and moisture through one installation.

Aprilaire’s Home Comfort Control system offers contractors a new way to talk about and sell IAQ products. The Home Comfort Control utilizes a touch-screen interface, which connects to an equipment control module with standard 3-wire connection, eliminating the need for separate controls for air moisture, air movement, and temperature.

“Home Comfort Control provides contractors with an affordable, simple-to-install and easy-to-operate control center for all IAQ products,” said Mike Rimrodt, marketing director at Aprilaire.

“This system gives homeowners confirmation and complete control of humidity, air cleaning, ventilation and comfort.”

Rimrodt said the Home Comfort Control allows contractors to solve the entire IAQ puzzle at once.

“It used to be that contractors might talk about adding humidity, taking humidity out of the air, or adding an air cleaner to a system,” he said. “Contractors can now have one conversation with a homeowner presenting the benefits of all IAQ products together as one sale — one system. It’s no longer about selling products. It’s about providing total solutions and control.”

Lennox’s Humiditrol, with 2-stage condenser, and the Healthy Climate whole home dehumidifier offer multiple air moisture control solutions. “Whole home dehumidification has really taken off in recent years, and Lennox has found that homeowners and builders are increasingly aware of the benefits of controlling humidity in the home,” said Kevin Lyons, IAQ product manager, Lennox Residential. “The advantages exist from both a comfort perspective, as well as an energy-saving perspective, in allowing the homeowner to set their thermostat higher without sacrificing comfort.”

Tim Storm, heat pump product manager, Residential Solutions, Ingersoll Rand, said residential, commercial, and industrial building owners are opting to use more and more technology in their systems, which offer greater system access and control.

“These new remote devices allow owners to be notified of a high temperature or humidity condition when away from the home so they can make adjustments from afar, or call for service, if necessary,” said Storm. “As efficiency levels increase over the next several years, I think we’ll see more use of variable-speed compressor technology and control algorithms, which optimize the efficiency and comfort levels within a home.”

Publication date: 8/6/2012