Story and photo by Santiago Hernandez
Directorate of Public Works
U.S. Army Garrison-Hawaii
Many people on Oahu experience mold issues at one point or another and why wouldn’t they? The Hawaiian environment is perfect for mold to reproduce, thrive and spread.
Mold growth only requires three things to prosper:
1- Relative humidity greater than 60 percent, such as from moisture from water spills, leaky roofs and condensation.
2- Food, such as dirty carpeting, dust, etc.
Furthermore, adding to mold issues are improper uses of heating, ventilation and air conditioning (HVAC/AC) systems, which contribute immensely to its proliferation. So how exactly are Soldiers, U.S. Army Garrison-Hawaii residents and employees expected to combat mold, and how do HVAC systems contribute to its growth cycles?
The solution is easier than you think.
“The very fact that people have mold issues at home or at the workplace says one thing. Their HVAC system is properly working as it was designed to do. So, if you see mold, technically, there is nothing wrong with your air conditioning system; however, the existence of mold means something else is wrong.
“From day-to-day, I conduct HVAC inspections throughout USAG-HI,” said Todd Hirayasu, USAG-HI Directorate of Public Works, mechanical HVAC engineer. “Many people assume, because they have a mold issue, there is something wrong with their air conditioning; however, many times that is not the case. Normally, I look for three things: One, operational hours of the unit; two, unit temperature set-point; and three, infiltration. Mold is normally caused by one or more of the above.”
Hirayasu added, “First, I check to see when the HVAC system operates. If I notice the system runs during nonoperational hours (during the absence of people and operational equipment heat), then it is highly expected that the relative humidity in the room will increase. When the moisture in the air increases and air temperatures are cooler, mold will grow. This is not good; however, running the HVAC unit for nothing is pointless (in many cases) and wasteful.”
He continued, “The second most important factor I inspect for is the temperature set-point (thermostat setting). The lower the setting and the longer you run a system, the colder you make the area. Relative humidity increases. The higher humidity effect provides mold the perfect opportunity to flourish.”
Leaky roofs, cracked windows and clogged drains, which condensate underneath systems, are the third leading cause of mold growth. Furthermore, inadvertently leaving windows and doors open, thereby letting warm moist air into conditioned areas, promotes the formation of condensation on cold surfaces This moisture buildup becomes the perfect breeding ground for mold.
So how do you reduce your chances of mold exposure?
According to Hirayasu, “First, only run your HVAC system during hours of operation, or when there are people in the room. Never run your system when no one is present. Allowing the system to run for no reason is financially wasteful and environmentally abusive.
“Second, choose a temperature set-point as high as possible, yet one that keeps you feeling comfortable. I set everyone’s thermostat to 74 degrees Fahrenheit – plus or minus 2 degrees Fahrenheit – especially considering, it is the USAG-HI set-point standard. I found out that this temperature setting happens to be equally good for the environment (energy conservation), occupants and as a mold deterrence.”
Hirayasu added, “Third, make sure there are no roof leaks and cracked windows in your home or office. Eliminate anything, which will allow warm outside air from making contact with cold surfaces in conditioned spaces. As previously mentioned, when this happens it provides a good starting point for mold growth.”
Combating mold and saving energy is easily achieved by following the same simple steps. Do not misuse your HVAC system. Have it on during operational hours, set at 74 degrees Fahrenheit. Operating it at lower temperatures and during nonoperational hours wastes energy and increases moisture or relative humidity.
Fix infiltration issues, such as leaky roofs, cracked windows and empty water pans. A combination of cooler temperatures and a moisture source provide the ultimate breeding ground for mold.
The same steps used toward combating mold are the same required to conserve energy. It is easy and everyone can do it. Let’s prevent mold and conserve energy at the same time.
Pass it on. Everyone is responsible for doing his or her part!
(Note: Hernandez is the USAG-HI DPW energy conservation manager.)