Q. I had a reputable company come to do air duct cleaning and they said there was mold in the hvac - therefore risky to do the cleaning because mold spores may go to other parts of the house.  They use fosters 40-20 as remediation and will charge an extra $1100 to treat everything with it.  The mold they showed me was growing on the vent in our bedroom and I was advised to get a new vent- the other vents aren't so bad so they will be cleaned and treated.  What do you think of all this?  [December 18, 2004]
         A. The U.S. Environmental Protection Agency [EPA] discourages duct cleaning because its benefit is only short-term and it cannot reach all mold and other contaminants living in the ducts and the heating/cooling system. If your heating/cooling system is mold contaminated, so is the rest of your house because the heating/cooling system is very good at distributing airborne mold spores everywhere in your home by its very operation of moving air to every area of your house. In addition, the most likely reason that your heating/cooling system is mold contaminated is that it was cross contaminated from one or more mold problems in the rest of your home. The operation of the system sucked in airborne mold spores from mold contamination sites to mold cross-contaminate the heating/cooling equipment and ducts. Your first step is to have the home thoroughly inspected and tested with a Certified Mold Inspector. Then mold remediate your entire home and the heating/cooling system at the same time. Learn the 25 steps for safe and effective mold remediation.

         Q.  I live in a town home in Woodbridge VA and just had my Fall Heater inspection.  We found major amounts of black mold inside the Carrier Air Handler that was not there in March.  The inspector first thought that maybe we could remediate it with ultraviolet light, but after considerable more checking said that it was too extensive and the unit would have to be replaced since it circulated air all through the house.  Is there no other means of killing mold inside a HVAC unit? [October 12, 2004]
         A. When there has been mold cross contamination of your entire house by a moldy heating/cooling system you need to mold remediate your ENTIRE house. Your first step is mold testing by using our do it yourself mold test kits to mold test your entire home for mold infestation. Test the air of any attic/basement/crawl space, garage, each room, and the outward air flow from each heating/cooling duct register for the possible presence of elevated levels of airborne mold spores, in comparison to your outdoor mold control test. Use do-it-yourself mold test kits [available from your local large hardware, home improvement, or safety store]. You should also collect samples of any visible mold for mold lab analysis and mold lab mold species identification by using the Scotch tape lift sampling technique explained on the mold test kit instructions of Mold Mart. Collect a different mold sample from each different mold growth location.  Learn safe, effective mold remediation tips. You can use also a low-cost Mold Home Remedy Recipes available at Mold Mart . The only perfect solution is the total replacement of your heating/cooling ducts and equipment after effective mold remediation of the rest of your house. You should test your home for levels of mold infestation in the heating/cooling system both before and after fogging a home mold remedy into your heating/cooling system. Your family needs to be out of the home during the fogging and spraying process [until the mold fog and spray are totally dried].

      Q. How do we know whether it is necessary to replace the ducts and the air handler because of mold contamination in my home? [Sept. 5, 2003]
       A. You need to know how seriously and where your home [including all of your heating/cooling equipment and ducts] is mold contaminated. Your first step to solve the problem is to mold test the air of each room, basement, crawl space, attic, and the outward air flow from each heating/cooling duct register for the possible presence of elevated levels of airborne mold spores, in comparison to an outdoor mold control test. Elevated mold levels signify a possible serious mold infestation problem and health threat. To use our do it yourself mold test kits, please visit: Mold Mart  Hire a Certified Mold Inspector. To know how to do mold remediation safely and effectively, please visit: Mold Removal. Before mold cleaning or replacing the the heating/cooling equipment and ducts, they should be first sealed [using plastic to tightly cover all return air registers and supply registers to stop any further mold contamination of the heating/cooling system. Then you would first complete mold remediation of all other areas of your house, including your personal property and clothing which should be mold decontaminated outside of the house in the clean room you can build pursuant to the instructions in our book Mold Health Book [Mold Mart]. Then you would use containment walls to seal off the mold remediated areas from the work that needs to be done on heating/cooling equipment/ducts. If the ducts are made of sheet metal [with NO insulation INSIDE the ducts], the sheet metal interiors can be effectively cleaned and disinfected with mold fungicides. If the ducts contain insulation INSIDE or are something like corrugated pipes, throw those ducts away and replace with new ducts.

Mold growth in air conditioning register duct.