6742 Forest Hill Blvd # 271, West Palm Beach, Florida 33413
888-381-6651
The following info is from two different mold inspections conducted withen three weeks of each other.
The findings on these mold inspections and many other similar mold inspections conducted by us show how proper placement of your AC return is important in detering mold growth and mold odor in your AC ducts.
The inspector inspected the master bathroom as well as the nearby closets where past leakage occurred through a glass block window.The inspector detected two mild distinct odors in the master bathroom that appeared to be related to microbial growth.One of the odors was the result of mold growing in the duct work that services the master bedroom and master bathroom area.In this inspectors experience the specific moldy odor detected in the bathroom AC ducts is almost always created primarily by a type of mold called Cladosporium spherisperium. This is not a toxic mold and does not produce many spores but it creates musty odors that can cause health complaints. This mold like all AC mold needs two things to survive:1) food2) moisture.Food is from dust in your ducts so use a good filter in your AC.Moisture is from humidity drawn in through the AC return so control humidity intake.Your AC return is near the bathroom and as a result this return will allow the AC to pull much humidity in from the bathroom after showers and baths, this is called entrainment and this inspector has seen many AC mold problems resulting from of AC returns near humid bathrooms or in other areas where
SPECIFIC AREA FINDINGS The above mold inspection was conducted in Boca Raton Florida on 1-22-08. The same type of mold odor problem was found 3 weeks later during a mold investigation at a similar luxury home in Wellington Florida near West Palm Beach. 2-12-08 mold inspection Musty odors were detected, musty or mold odor detection is an important part of any mold investigation because it lets us know that a little mold is present even if it cannot be visually detected. In addition, even when spore levels are low. Minor mold odors were in the following area(s) in the master bedroom when the AC unit was on. The odor detected was typical of that from AC ducts and is not like the odor produced by the many molds that grow in walls. It was detected near the ducts and only when the AC was on. This was occurring because the AC return is near the master bathroom, this allows the AC to pull humidity into the AC after showers and baths. This humidity condenses in the AC and ducts and allows small amounts of mold to grow in the AC and ducts. This mold inspector has seen this exact same problem in similar homes, and the inspector has seen many mold problems caused under various similar circumstances when AC units pull humidity in, this is called entrainment. To correct the condition the AC and ducts and main supply plenum for the master bedroom AC will have to be cleaned by a professional who follows NADCA standards and the AC return will have to be moved to a different location in the same zone, a location not so close to the humid bathroom. Please be aware that this was not a serious mold problem and this does not mean that this is a moldy house, it is a nice house and did not have evidence of a serious mold probelm. This was just your typical minor musty or moldy duct odor and it may not be detected by all persons. Only sensitive persons with allergy or asthma would be affected by such a condition but based on this inspectors experience with this degree of odor some persons can be effects by such odors.
Two Common Causes Of AC Mold
January 6, 2008
Some people believe that AC ducts are destined to become moldy. While all AC ducts will likely grow some mold and will become discolored with visible mold or visible dust to some degree, it is not normal or healthy for ducts to become excessively moldy, or to produce a strong mold odor.
Mold spores from AC ducts result in health problems and even mold odors in the absence of spores have been shown to cause health problems. Keeping ducts free of excessive mold is important.
The information in this blog is intended to provide readers with information on:
1) Some reasons why AC ducts become moldy.
2) The importance of proper sizing of AC units.
3) In addition it draws attention to a very common indoor air quality problem called entrainment. Entrainment is when AC units pull contaminated air from inside attics or walls or other undesirable areas.
The following information is taken from a Broward County mold inspection we conducted on 11-17-07 it shows an actual example of how ducts became moldy and gives recommendations at the end.
The property inspected is a one story single family Broward county house built in 1974.
Client reported mold growing on AC vent registers. The mold started a few weeks ago. The client reported that a new larger AC unit was installed about 3 months prior to the mold starting. This inspection is for mold conditions at the AC registers only.
Location: Garage:
In the above referenced area the inspector observed a new air conditioner. The serial number on the unit indicates that it is a 4 ton unit, thus is it rated to cool a 2400 sf house. This AC unit is just a little large for this house.
The inspector also observed a new condenser / compressor unit. The serial number indicates that it is a 3.5 ton unit thus designed to cool a 2100 sf house. This is also slightly large for the house.
You have a newer larger AC unit.
The size of this newer AC unit is a major reason for why you have humidity related cladosporium on your AC registers that were previously not moldy.
The previous AC unit in use about 3 months ago was smaller than this AC system thus would have been more efficient at drying the houses air before cooling the houses air and shutting down. If an AC is to large it shuts off after the air is cooled but before the air is properly dried / dehumidified. Air that is not dehumidified and has a humidity above 60%RH to 65%RH can and often does cause humidity problems in Florida homes.
The above photo is of cladosporium mold growing in your registers.
Another reason why you have mold problems now is because of the two holes in your AC return. These holes in the wall studs allow the AC to pull humidity into the AC each time the AC turns on, this phenomenon is called entrainment and is a common cause of mold and humidity problems.
Yes all metal studs have these holes, but it is not typical for these open holes in the studs to be exposed and in such close proximity to an AC return.
Where does the humidity in your walls come from? it comes room the attic, the attic in turn gets the humidity from outside via the soffit vents like the one in the above photo.
Why did this problem not occur till recently? the older smaller AC was more efficient at drying air as stated above and thus was able to handle the humidity load created by these openings.
More photos of mold on and around your AC registers. Note that the tiny black spots on and around AC registers are very typical examples of cladosporium spheasperium, or cladosporium cladosporidies mold. This mold problem is caused by elevated humidity in your ducts.
This is not likely to cause a toxic reaction, but this mold may result in allergic reactions or act as an asthma trigger in sensitive persons. The real concern is if it is growing excessively deep in your ducts then you will have much more mold than you can see on the registers.
Mold growth in the ducts can and often causes health complaints.
Excessive mold was not observed in your AC unit but you are recommended to have your ducts cleaned in accordance with NADCA standards or replaced.
More photos of mold on and around your AC registers. Note that the tiny black spots on and around AC registers are very typical examples of cladosporium spheasperium, or cladosporium cladosporidies mold.
Based on this inspectors observations and conclusions your inspector recommends using good quality foil mastic tape or other methods to seal two openings in your AC return wall studs.
Have a AC company install a humidistat and set it to around 50% to 60%RH always maintain indoor humidity between 30% and 60%RH.
Most people live with a little mold in the ducts and have no problems. Mold spore levels in your air was very low. No mold odors were detected. Much of the mold appeared to be primarily in the ends of the ducts just behind the registers.
Have an AC company clean the mold from the registers and from the ends of the ducts just behind the registers.
Duct removal or good professional cleaning in accordance with NADCA standards is recommended if additional hidden mold is discovered inside the ducts during cleaning.
Daryl Watters is president of A Accredited Mold Inspection Service, Inc. He provides home, mold, and indoor air quality investigations in South Florida. He is also the creator of MIR forms designed to aid inspectors in the production of computer generated indoor air quality and mold inspection reports.