Mold prevention, control: keep things clean, dry Published May 28, 2015 By Mike Jago 14th Civil Engineer Squadron COLUMBUS AIR FORCE BASE, Miss. -- Welcome to Columbus, Mississippi, the Friendly City. Allow me to introduce you to your new neighbors, mold and mildew. Actually, they are like Superman and Clark Kent; the same person just different disguises. Warm, damp weather promotes mold and prevention is a must. First things first, you should know your enemy. Despite what many people may assume, mold and mildew are the same thing. The mildew in the bath is mold and the mold on bread is mildew. There are thousands of different types of mold, ranging from black to red, blue, yellow and the common green. Technically, mold is a plant. There are so many types, most are not yet named. Mold can grow just about anywhere it can get some water, light and something to grow on. Our troublesome mold needs warm and humid surfaces to live on; this is where you can stop mold before it starts. Temperature and humidity are key in prevention. This can be tricky since mold has a wide range of growing temperatures, but a limited humidity band. Mold does not grow in hot, dry places, it instead likes the same temperatures you probably like, around 70-80 degrees Fahrenheit. According to a University of Florida study, mold doesn't live and reproduce below 68 percent humidity. If we cut humidity below 68 percent to a nice comfortable 50 percent, problem solved right? But how can that be accomplished? Humidity is the amount of water in the air and derives from opening the door, showers, sinks, washing machines, refrigerators, and even sweating, breathing, cooking and sleeping. The warmer the air, the more water it can hold, so cooling it makes the water condense, or "fall" out of the air. Air conditioners do a great job of squeezing the water out, but only if they are operated correctly and set up right. Here are a few quick pointers to dry out the air without running up the electric bill. With air conditioner systems, they are set up to cool quickly and drop the temperature quickly, or cool gradually and slowly so it has time to dry the air. To be comfortable but not cold, dry the air by making sure the air conditioner is running longer, so it has the critically-needed time to dry the air. If it is blowing the air out of the vents vigorously, the coils may never get a chance to form condensate. This condensate can also cause "snow" out of the vents, or wetness and mildew in the vent pipes. The dew point is the critical factor here, not how cold the air is. If the temperature is below the dew point, which is around 65 degrees Fahrenheit or warmer, the area will cool quickly but the vent will form water, and that is the start of a mold problem. Overcooling can also cause moisture to form on walls, furniture and even windows as they cool below the dew point of the room. This can cause major mold problems. Energy is often a concern, and having your air conditioner serviced is the first step to energy efficiency. Low or high pressure in the freon will make the system work inefficiently. Fans need to be set to move air at the right speed. If your system is 10 or more years old, it may be time to invest in a new one. The efficiency of many new machines is so good they could pay for the installation in less than three years in energy savings alone. I moved from a 20-year-old system to a proper new system and it paid for itself in two years. Don't forget to change filters monthly and put in HEPA-rated filters during pollen season to help keep the system and your living area cleaner. This leads to a great argument of what I call "thermostat wars." What is the right setting? Here in Mississippi, it is all about the humidity. Get a hygrometer, or a relative humidity meter, normally sold for as little as $5. Use it to try and manage humidity to below 70 percent, but above 40 percent. To achieve this ideal humidity, adjust the thermostat where your air conditioner will not run. Let it sit for about five minutes to make sure. Then set it down two degrees. Let it cycle and watch the hygrometer drop. If after overnight it has not dried the air and the air conditioner is cycling normally, set it down another two degrees. If this doesn't drop the humidity to 60 percent or lower, get the system serviced and explain you are trying to get a wet bulb temperature of around 75 degrees Fahrenheit. Problems may arise if the cooling area is not well insulated or gets lots of outside air. Business offices or children running in and out will cause the same issue, which may freeze your air conditioner into a block of ice. This is a combination of high humidity and no off-cycle time for the unit. Air conditioner units need to cycle and push air through to dry the coils. Many cars have the same problem. Mold cannot grow on a clean surface. Keep areas that mold easily clean and dry and don't be afraid of it. If it is really bad, spray it down with any cleaner with bleach in it and let it sit for a minute before wiping it up. Wet, soapy mold will not give off spores, which is what gets the allergies going. The dreaded "black mold" is a very specific variety and rarely found. You may believe you have it, but it is far more likely you have one of the other 20,000 varieties that are just annoying. In conclusion, check the air's humidity. High humidity is unhealthy and creates breeding grounds for mold. If you see it, clean it and get cracking on controlling the humidity. For facility managers and supervisors, the policy for all U.S. Air Force installations is: 1) User must clean mold first 2) Take actions to control humidity 3) If humidity remains high and mold returns, put in a work order for HVAC service after step 1 and 2 For more information about mold control and prevention, go to the EPA website, epa.gov/mold/preventionandcontrol.html , then try 434-7974.