In many countries around the world the chimney sweep serves as the building inspector and the expert on all things heating, air conditioning, and ventilation. This came to be because the chimney in homes requiring heating with fossil fuels is the center of all things having to do with indoor air quality. If you think about it, this makes a lot of sense. If the chimney is blocked, is not pulling enough air, is not tall enough, is subjected to winds, allows water to come down, does not exhaust enough gas, or does not have enough fresh air to makeup for air that is being exhausted indoor air quality suffers, and so do the occupants. Look it up someplace (Google, WebMD, ASHRAE, ARI, IAQA) when indoor air quality is poor the occupants of the space (building) can develop new health problems or existing health problems can become worse.
Here in the United States, especially in Florida, your licensed Mechanical Contractor with Indoor Air Quality experience and training is the equivalent expert to the old chimney sweep. You say, “we don’t have a chimney” which is very true, but we still have things that can affect your indoor air quality. And where the chimney is the central part of maintaining air quality in European countries and areas that require heating, in areas where we primarily cool the Air Conditioning and Ventilation systems are the primary source for indoor air quality.
We talk about “Air Quality” but we have yet to provide any example of what affects air quality, let’s fix that. In most buildings air quality is the ratio of pollutants inside the structure vs outside the structure. The quantity of pollutants inside the structure should always be lower than that found outside. So, what are these pollutants we talk about? They could be:
1. Dust particles
2. Bug feces
3. Microbial growth
4. Volatile Organic Compounds (VOC’s)
5. Carbon Dioxide (CO2)
6. Carbon Monoxide (CO)
7. Humidity (too much or too little)
8. Animal feces and urine
9. Off-gassing from electronics
10. Fiberglass from the fiberglass ductwork
Recently I visited a home where the homeowner had just paid to install close to $3600.00 of ultra-violet lights, electronic air cleaners, and done a full duct cleaning at an additional $1500.00. The homeowner shared the service ticket from her Class A Air Conditioning contractor with me. It stated, “because of recent hurricane damage we recommend installation of UV Lighting to kill mold, and additional filtration to remove mold spores from air,” the technician representing the contractor went a step further and stated, “addition of this equipment will improve homeowners breathing.” After I read this and poked around the home a little bit looking at ductwork, looking at the installed equipment, and checking some technical specifications, I asked the homeowner for the results of the air samples that the contractor must have taken before making the recommendation. The homeowner told me that no air samples were taken. Now, too avoid a war I chose not to go forward with the conversation. But, the bottom line was that a senior citizen, on a fixed income, was severely taken advantage of. There are no laws against this, but is is unethical and just bad business practice.
Evaluating the above scenario. First, you would never walk into your doctors office and have him or her diagnose you with a deadly disease without testing. Diagnosis without testing is malpractice. The preventative maintenance technician that came out and did the $50.00 air conditioning inspection in the above case did no testing. There was no way for anyone to know if there was or was not mold spores in the air or in the ductwork. The other major problem with this scenario is that the technician referenced this as a solution to the customers’ health issues without having the proper training to do so. If he/she had the proper training they would have never made such a diagnosis without testing. Third, they were assuming the problem could be solved with the air conditioning system. Again, without proper testing there is no way to know there is a problem, or where the problem originates from.
Some indoor air quality problems (like the above pictures) are obvious that they exist, the building on the wall above has microbial growth. but, do we know how to solve, what caused it, and how we can prevent in the future without proper training and testing? No, at this point just by looking at the building you cannot even say for sure the growth is mold, nor if it is in the air ducts.
The pictures above are from the same building. So, does the ductwork have mold in it or not? I can guess probably yes, but does the ductwork look moldy? Do the ceiling diffusers look like they have mold or microbial growth on them? No, but how can you be sure without testing. Will additional filteration or even Ultra Violet lights do anything to solve this problem? Will it make it safe to breath the air? Is there even an air quality issue? A technician can guess that there is, but the only thing they should be putting on paper is, “I recommend getting the air in this space tested to see what if anything needs to be done with air quality.”
I was at another location recently and found what appeared to be microbial growth on the air handler (the indoor portion of the air conditioning system). After talking with the homeowner I learned that this has been a problem for many years and that their contractor’s technicians has always told them that “this is Florida and you will always have mold, it’s expected.” Well, partially the technician is right and I will give him two points: First, yes, this is Florida and second, mold is a part of our natural environment. The problem is that we should never see such a high building up microbial growth in one location.
Would it be right for me to scare a homeowner or business owner by saying this is mold? No, without testing I can suspect it is microbial growth but I can’t say it. Can I tell a homeowner that additional filteration and a UV light will resolve this issue? No, because without testing and evaluation a technician does not know the cause. Is this a normal condition in Florida? No! There should not be mold or any signs of water damage on the outside of a proper functioning and insulated air handler.
What does it take for mold or any microbial growth to grow?
1. Water or Humidity
2. Something porous to grow on
3. Proper temperatures
Florida is known for it’s humid and somewhat warm environments. Humidity above 45% has the ability to hasten mold growth. The ductwork on most air conditioning systems in Florida is made from Ductboard. This is a compressed fiberglass material that is cut and folded into the appropriate shapes. When ductboard gets wet it begins to loose it’s structure and starts to catch dust and dirt, and will retain moisture. The white coating found on ductboard around the connections to the air handler is also porous. It also has a tendency to catch dirt and other debris. Based on the requirement list above we have live in an area that is prone to mold growth. That does not mean it is acceptable, nor should it happen.
Looking at the fifth picture above, the one with the side of the air handler and the plenum you can see where the growth is originating from. It is at the seam between the duct and the metal cabinet. Let’s take a quick step back. As a mechanical contractor I cannot control the fact that we live in an area with proper temperatures for mold growth. Sure, if the system is inside the house it is a little more controllable, but if it is outside or in the garage I am stuck with that. I am unable to control what the ductwork is made out of. I am unable to control what happens when a customer opens and closes the doors (well, I am, but that is another story). The one thing I have control of is moisture and humidity.
The primary purpose of air conditioning is to dehumidify and then cool. Think of it as a cold glass of ice water on the counter in a hot humid room. If you leave the glass for too long you will have a puddle of water on the counter even though the glass does not have a leak. This is what your air conditioning does as it cools the temperature. The humidity from the air is removed and piped outside the building. If the humidity is not removed, or if the unit gets too cold and starts to sweat on the outside, we now have a water problem and water is one of the main requirements for microbial growth.
The second important part of any HVAC system (Heating, Ventilation, and Air Conditioning) is Ventilation. There is an old saying, “the solution to solution is dilution.” If you have a bottle of water that has a chemical in it. Then you dump that bottle into a 50 gallon drum of water, will you have the same levels of the chemical? No, because it is now diluted with a large amount of water. The same goes for air. If I have air that is poor quality inside a building, and I bring in enough fresh air, all of a sudden the indoor poor quality air is diluted by the larger quantity of fresh air. Did you know that in commercial buildings code says that we must bring in a percentage of outdoor air per hour while the building is occupied? But, yet in residential buildings, this is left up to local code requirements and most do not have this requirement.
So, how can a properly training Mechanical Contractor assist with the diagnosis and the resolution of these indoor air quality issues? And what can’t they do as it is beyond the scope of their licensing? Stay tuned for the next part in this series.
Christopher Molnar is a proud member of the Indoor Air Quality Association