Quality air filters, sealed ducts will keep mold at bay

Q: I need to call someone to clean my air conditioner and whatever else is included. Who or what type of service company performs this job? Also, what should I be having done to my unit and/or inside ducts and furnace? I want to make sure there is no mold or anything when this has been performed.A: It seems as though our news services have done a good job of making the public aware of mold problems inside the home, the office or other workplace.There is no doubt that some people suffer from what is known as "sick building syndrome," or SBS, and you need to educate yourself on what these problems might be.With heating and cooling costs taking a larger share of our income, homeowners, landlords and building owners are doing all they can to prevent air infiltration by insulating, caulking and sealing any opening they can find.Consequently, by reducing the amount of air infiltration to the building, the number of air exchanges that existed before the sealing is also reduced.Previously, the air exchanges would purge the breathable air of any number of unhealthy chemicals, hydrocarbons, pet dander, volatile organic compounds and mold spores that are commonly found in homes, offices and especially manufacturing buildings.Any airborne particle that might have some adverse affect on your health will eventually be sucked into or blown out of the HVAC (heating-venting-air conditioning) ducting system.The first line of defense against airborne contaminates is a good-quality air filter and a closed and sealed filter access.If the filter-access panel is left open, it will expose the filter to carbon monoxide and hydrocarbons from fossil-fuel-burning appliances and to mold spores and chemical vapors, all of which can be sucked into the fan system and distributed to the entire building.The second line of defense is to make absolutely sure that all of the ducts, both the supply and return air ducts, are sealed at all joints, seams and at take-off points that lead to registers and grills.Every three to five years the ducts should be cleaned by a trained and professional HVAC technician.If the lining of the ducts has a glued-on insulating material, air samples should be taken to see what type of mold spores are present and in what quantities. However, even sheet-metal ducts can harbor dust and mold spores once the linings have become oily and sticky.Living with mold and mold spores is a fact of life. We have to share this planet with molds, but we do not want to keep feeding the little creatures until they drive us from our homes.The molds, which are present in ducting systems, can be removed with a HEPA (high-efficiency particulate air) filter and/or with an ultraviolet lighting appliance that can be added to any return air duct system.Mold spores can also thrive on the dark and damp cooling coils that are a part of the air-conditioning system. In residential applications, the cooling coils are a part of the furnace and fan system and should only be inspected and cleaned by a professional HVAC technician.The slightest damage to the thin-walled metal tubes could release the coil's refrigerant contents to the atmosphere. A damaged coil generally has to be replaced rather than repaired, which is a very expensive mistake for a homeowner.The outside unit of the air conditioner also has a set of thin-walled metal tubes that can be cleaned by either a homeowner using a garden hose or by the HVAC technician.Molds, which might form on the outside unit, cannot reach the home's indoor environment through the refrigerant piping. The outside unit's coils should be cleaned annually.You can test the indoor air yourself by purchasing test kits from Lowe's or Home Depot or online at http://moldtestkit.com.(Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home improvement questions at C. Dwight Barnett, Evansville Courier & Press, P.O. Box 286, Evansville, Ind. 47702 or e-mail him at d.Barnett(at)insightbb.com.)