Humidifiers Can Cause Mold Problems

           Q. We were recently looking at homes to purchase when we ran upon a home we are very interested in. We have been in the home twice. Upon the second visit we noticed a spot near the baseboard trim in a support column that is drywall. When I pushed on the spot it felt damp and soft. I picked at it and noticed it looked like mold. We then proceeded to find one other similar spot. The home was built in 1993. We checked the attic crawl space and found no apparent signs of water or any leak. The house has been empty and no dehumidifier or air conditioning has been running. There is a humidifier installed on the furnace. We now think they house may have been over humidified. Obviously we now know this house has a problem and feel someone qualified should take over.  My question is: Since we have not made an offer and have no obligation in this home, what should be done by the owner or realtor in this situation. We are very interested in the home and were considering making an offer. We want to be sure the house is repaired and the mold issue is resolved before purchasing it. We don’t want the mold repair to affect the purchase price negatively for us. I’m afraid if the owner fixes the problem they will want to add on to the price or potential offer they would have taken prior to the mold issue. Any advice would be appreciated. [Sept. 4, 2005]
         A. You are absolutely correct that operating a humidifier in the home may be one of the causes of the water and mold problems inside the wall materials. A humidifier is never appropriate for use in a home or other building because elevating indoor humidity invites mold to grow everywhere. Usually, homeowners need to use a programmable dehumidifier to keep indoor humidity year-round to a mold-discouraging 30 to 40%.  You need to have the home inspected either by a Certified Mold Inspector  or by using do it yourself mold test kits from a large hardware, home improvement, or safety store. Don’t expect that the realtor or owner will do expensive, safe, thorough mold inspection, testing, and remediation. If there is a large amount of hidden mold inside walls, ceilings, floors, attic, and the heating/cooling equipment and ducts, you will end up spending thousands of dollars in mold remediation even with the do it yourself mold removal steps explained at Mold Remediation.  Even if you can find and fix all hidden mold infestations, you would still own a home with a mold history that you will likely have to disclose to prospective buyers and tenants in the future.  

        Q. Our home has a furnace with humidifier built in. We have been here 8 years, changed the furnace filter yearly but did not know there was a filter for the humidifier. After having turned the heat off during a warm spell in April and then back on -Oh that smell was so distinct. When my husband found the source of the problem, he said it looked like the previous owners had never changed the filter either. My son would get sick at night-vomit-then be fine in the morning. This happened maybe five times over the course of the winter. He also has been very congested and short of breath easily. I also was diagnosed with asthma after an episode that took me to the hospital about a year ago. My husband did change the filter and sprayed in and around with tilex. So I guess my concern is that should my son and I be seen by a physician or are we safe to presume that if the mold is gone we should be fine. [May 7, 2005]
        A. In addition to likely massive mold growth in the humidifier itself---mold growth that will be spread efficiently by the heating/cooling system to mold cross-contaminate the entire house---the humidifier in operation significantly increases indoor humidity to facilitate massive mold growth through out your home. It is extremely unadvisable to operate a humidifier. Remove it permanently from your system. You need to maintain a 30 to 40% indoor humidity to discourage mold growth. To maintain a mold-safe humidity level, many homes need to operate one or more DEhumidifiers.  A one-time cleaning of the dehumidifier does not get rid of the mold cross contamination that has already spread inside the heating/cooling equipment and ducts and the entire house. In view of the humidifier problem and your family’s serious mold health symptoms, you would be very wise to do entire home mold testing on a do it yourself basis to learn the extent of possible mold cross contamination. For inspection and testing tips, please visit: Mold Inspection. Learn the 25 steps for safe and effective mold remediation.

       Q. I am not sure if I have a mold problem or am creating one by way of our new furnace with built-in humidifier. We installed it last winter and were shocked to see the extreme dampness on all our Andersen windows the next morning after a cold night.  The beading water trickled into the corner of every wooden window frame.  We are constantly wiping the windows and frames every morning.  Our windows (We're talking about a full Florida room with 75% window space and most of the rear of the house-north facing...17 large windows in all) are shaded with honeycomb like shades that can cover the entire window, thus not letting any air out.  Also, the dampness from the humidifier has now crept up to the ceiling of every room with a skylight.  Those areas of sheetrock are now showing water stains as well and are the reason I'm seeking advice on possible mold damage. Is it impossible to have any working humidifier for a furnace?  As it was previously, the winter months provided very dry, choking heat from our old forced hot air system, so we replaced it with the new system/humidifier.  But as it is now, we have the humidifier almost turned off completely to avoid further dampness damage.  After inspecting the "moldinspector" web site, I see nothing about mold damage from a furnace/humidifier and I am at a bit of a loss to try and find a solution or information about how to proceed?  Do I need to do a mold test? [November 29, 2004]
      A. Running a built in humidifier, or a portable humidifier, or a vaporizer can significantly increase indoor humidity to make mold a permanent house guest if such humidity inputs are used on a regular basis. Because of the serious threat of mold infestation to family health, you would be wise to never again utilize the humidifier [which may also reduce the value of your home because smart prospective buyers will perceive the existence of the built in humidifier to be a red flag about probably mold contamination in your house]. Because of the heavy window condensation and the evidence of water damage on some of your sheetrock, you need to be concerned about whether your home is now mold contaminated. Your first step is to have the home thoroughly mold inspected and tested with a Certified Mold Inspector or by using do it yourself mold test kits from a large hardware, home improvement, or safety store. You should also buy a $30 digital hygrometer from a large hardware store, Lowe's or Home Depot to regularly check your indoor humidity year-round in different areas of the house. If the indoor humidity is 60% or more that is going to result in big-time mold problems. Your goal is keep the indoor humidity to 30 to 40% which discourages mold growth. Many homeowners and tenants utilize a programmable dehumidifier to keep the humidity level that mold-safe. Become your own effective mold expert to improve your personal home or apartment environmental safety and/or the environmental health of your investment properties by reading all three of our mold advice, email delivered books [Mold Health Guide, $15; Mold Legal Guide, $15; and Do-It-Best-Yourself Mold Prevention, Inspection, Testing & Remediation, $15, plus Mold Remedy Recipes, $15].

      Q. My doctor suggested a humidifier for breathing problems.  It brought my small apartment from 50% humidity up to about 63%.  It had no automatic shut off.  I refilled it every 24 hours without emptying the residue and wiping it out with vinegar.  I have limited use of my right hand and arm from radiation nerve damage 22 years ago. My thoughts were I would clean it really well at the end of the week.  About the sixth day I noticed whitish residue all over everything in the room with the humidifier.  I cleaned it and put it away.  Not long after that I started getting the sniffles, which seemed to blossom into a full-range chest cold.  After coughing up ugly green stuff for a week and it becoming blood-tinged and throat now being sore, I sought advice from my doctor.  She could find nothing with her stethoscope and I had no fever - did several tests in her office and some at hospital, the results of which are  not in.  Since it all continues and glands are now swollen, with a continuing salty taste to any water anywhere, I'm getting anxious about living with the residue I cannot see on my walls, etc.  If there is mold there, even if I have everything cleaned by "experts" - will that be enough? Would an ionizer be in the best interest of my future health?  If so, which type would you suggest.  My space is about 500 sq. feet. {April 25, 2004]
     A. An ionizer is worthless for mold problems. You should NEVER use a humidifier if you value your health and possessions. Humidifiers increase humidity [their design goal], enabling mold to grow everywhere, including on all of your possessions, on and inside walls, ceilings, floors, carpeting, and inside heating/cooling equipment and ducts. You need to buy a $30 hygrometer from Home Depot or Lowe's to measure year-round the indoor humidity of all areas of your apartment. Your indoor humidity needs to be at a mold-discouraging 30 to 40%. You may need to operate a programmable dehumidifier set to run automatically, as required, to maintain a desired humidity setting in the 30 to 40% range. In view of your health problems and the likelihood that the residue is you see everywhere is mold, you need to mold test your apartment. Your first mold investigative step is to use do it yourself mold test kits from a large hardware or home improvement store [with self observation of results over a 5 to 7 day time period, or send in for mold lab analysis] to mold test the air of each room, attic, basement, crawl space, 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 which you should also do. If you see any visible mold growth, from each moldy area, scrape some of the mold particles into a separate mold test kit per testing location for observation over a 5 to 7 day time period, and/or for mold lab analysis. When scraping mold into a test kit, you would be wise to use a breathing air respirator [Home Depot or Lowe’s or a safety store] so that you don’t breathe in extra mold spores that you put into the air by scraping some mold-like substances into each mold test kit.   Use do  it yourself mold test kits from a large hardware, home improvement, or safety store.  Learn the 25 steps required for safe and effective mold remediation.

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