Do You Have a Sick House? The Mold - Air Duct Connection
-
1-10 hours
•
-
Beginner
•
- 0-1,000
A sick house is a house with a serious air quality problem. An area can be described as "sick" mainly because people who reside inside it for an extended period can develop symptoms of illness such as headaches, watery eyes, nausea, skin disorders, and fatigue. The illness causing factors vary and can include a build-up of air pollutants from household products, building materials, formaldehyde, and/or respirable particles.
In humid climates, sick houses are usually houses with a serious moisture problem. Moisture also plays an important role in promoting the growth and spread of mold (mildew). Molds produce spores, tiny encased "seeds," that float in the air. When a home is severely contaminated, thousands of mold spores can be suspended in each cubic foot of air. When people are repeatedly exposed to mold spores, they can develop allergic symptoms.
1. How Air Conditioners Cause Mold Problems
Visible mildew and mold is easy to identify because of its discoloration and odor. Keeping humidity in a home low can help keep visible mildew from returning, but if mold spores get into the air conditioning system, they can settle in the air conditioning ductwork, along with dust and other contaminants, where you can’t see or smell them. This is a worst case scenario because duct systems in humid climates are incubators for microbial pollutants like mold and bacteria. With the alternating high and low humidity conditions that regularly occur in air conditioning ducts during normal AC use, mold will grow, produce spores, and spread throughout the house.
2. Soil Build-up in Air Ducts
Effective filtering is a huge part of keeping ducts clean. If you have pets, plants, or other unique factors at play in your home, consider upgrading to a newer kind of filter the next time you swap them out. Newer filters can now remove smaller particles, and more of them as compared with the older fiberglass filters.
By neglecting to clean or change your filters, the build-up of dust and dirt on air conditioning filters causes air to by-pass the filter and carry organic dirt and spores into the ducts.
Leaks around duct joints in attics can also introduce dust and spores.
3. Duct Moisture
Moisture in air ducts is nearly unavoidable, as the air leaving the evaporator becomes saturated as part of the AC’s normal process. If you run your air conditioner for the majority of the year, this leaves little time for that saturation and moisture to actually dry up.
High moisture can cause any dirt present in the duct to become caked on and provide an environment for mold to grow. The best way to address this issue is to either use the air conditioner less frequently or to clean the ducts regularly to clear out any caked on dirt and moisture.
4. Cleaning Air Ductwork
There are many different methods for cleaning ductwork, but because air ducts are such complex, closed systems, it is often difficult to maneuver equipment through them to clean or even locate every specific patch of dirt or buildup.
Most methods involve the use of shop vacs and motorized brushes, and while a dedicated professional can remove a fair amount of dirt with these tools, it is time consuming and the worker is often limited by how far though the duct their equipment can snake. More expensive options clean using essentially the same principle, but with larger and more powerful equipment.
Depending on the service you employ for this part of your ductwork, they may even use fiber optic camera feeds to see what the distant interiors of the duct look like and may actually cut in to certain points to remove localized instances of dirt or other harmful build up.
Another key factor is that none of these methods address the deeper concerns about mildew, molds, bacteria that can be a problem in humid climates, especially in fiberglass lined ducts.
In such cases, even a biocide specifically made to kill the mold may not be able to be put to use, since the presence of the biocide in the ducts and air that people breathe would be questionable and potentially harmful.
-
![Jason Pelmont]()
Jason Pelmont has an expansive background writing and editing content. He began writing articles for small local publications as a student and was a reporter for his school paper. After completing his degree at California State University, Northridge, Jason worked as a freelance writer and editor. Beyond creating articles for print and web, his experience included work as a researcher for the L.A. Times, copy editing for advertising firms, and writing broadcast journalism content.   Creative writing endeavors include fiction pieces and screenplays. Jason has written shorts and feature films, sold scripts to production companies, and was recognized with the Martin Roth Memorial Screenwriting Award. As an intermediate DIYer Jason has enjoyed projects that range from woodworking and flooring, to whittling, crafting, and jewelry making. Like most DIY enthusiasts, Jason’s dream project is to build a wildly impractical home with a slide instead of a staircase despite the fact that his day to day projects are more likely to include quick fixes in the garden or small maintenance repairs to home decor and appliances. When not pursuing new stories, Jason is an editor for DavesGarden.com and videographer for DoItYourself.com. Check out the latest home improvement projects and tips on our DIY YouTube channel.![Dawn Hammon]()
Dawn Hammon has thrived in freelance writing and editor roles for nearly a decade. She has lived, worked, and attended school in Oregon for many years. Dawn currently spends her days convincing her children she is still smarter than them while creating new experiences with her husband of 24 years.  Her multiple interests have led her to frequently undergo home improvement projects. She enjoys sharing the hard-earned knowledge that comes with it with the audience of DoItYourself.com. Dawn and her sister make up a power-tool loving duo that teaches classes to local women with the goal of empowering them to tackle their fears and become comfortable with power tools. Tapping into her enthusiasm for saving money and devotion to sustainable practices, Dawn has recently launched a passion project aimed at connecting eco-friendly products and socially-responsible companies with consumers interested in making conscientious purchases, better informing themselves about products on the market, and taking a stand in favor of helping to save the planet. When she is not providing stellar online content for local, national, and international businesses or trolling the internet for organic cotton clothing, you might find her backpacking nearby hills and valleys, traveling to remote parts of the globe, or expanding her vocabulary in a competitive game of Scrabble. Dawn holds a bachelor's degree in psychology, which these days she mostly uses to provide therapy for her kids and spouse. Most recently, I worked for a small local professional organizing and estate sale company for four years where I learned a ton about organizing and/or disposing of just about anything. She was raised in a tool-oriented, hands-on, DIY family. Her dad worked in the floor covering business and owned local floor covering businesses, so of course selling floor covering was one of her first jobs. Her brother was a contractor for about 30 years and site supervisor for Habitat for Humanity. I worked with him often, building decks, painting houses, framing in buildings, etc. With her sister, she holds power tool classes to empower women who are scared or have never used them. Not quite homesteaders, she did grow up with a farm, tractors, motorcycles, expansive gardens, hay fields, barns, and lots of repairs to do. Plus she and her family preserved foods, raised cattle and pigs, chopped and hauled firewood, and performed regular maintenance on two households, outbuildings, fencing, etc. As an adult, she has owned two houses. The first one she personally ripped out a galley kitchen and opened it up to the living area, plus updated every door, floor covering, and piece of trim in the place. In her current home, she's tackled everything from installing real hardwood flooring to revamping the landscape.
