That Musty Smell in Your Home Might Indicate That You Need To Clean Your Air Conditioner Evaporator Coils
It is very important to check your AC drain and pan during the summer
Have you recently turned on your air conditioner in your home and noticed a musty or moldy smell? The solution may be to clean your air conditioner evaporator coils. These coils are situated within the air stream of your furnace/air handler. Because of where they are located, these coils accumulate dust particles and dirt that is circulated within in the ductwork of the HVAC system. When your thermostat is turned down and calls for cool air, the system will respond and start to circulate. As the cold air conditioner coils are exposed to the warm moving air, condensation results. This water runs down the coils but they natually will remain wet; As a result any dust that gets blown through system will then “stick” to this damp metal. When enough condensate builds up it will run down into the drain pan below carrying with it some of the collected dust. The pan has a small drain pipe that will either lead outside the home, into the crawl space or to the condensate pump. It is important as a homeowner to know where this drain area is so that you can check for a clog or blockage. If it is blocked, the condensate water will collect and remain in the pan below the coils. This is a breeding ground for mold. Anytime the relative humidity in the air is above 60% and a food source of organic materials such as dust and/or construction debris is present, mold can grow.
There are a few things that a homeowner might notice that would indicate that your drain plug may be clogged. There may be water near or under your furnace or you may notice a musty smell when your air conditioner is blowing. You may also have a secondary drain on the system that could be dripping water. These drains are often located in a conspicuous location on the home, such as above a doorway or off a roof line, so that you would be sure to notice the drip.
Sometimes the drain pan under the coil is not sitting level and the water will naturally collect in the “low” end instead of draining. We do not do repairs such as this, or others to your HVAC system, but our technician will alert the homeowner if he notices a defect such as this. Often this leaning can occur when a house settles; the builder or plumber may have originally set the pan properly but after a few years the foundation may have shifted and settled just enough to affect the drainage. If you have a low end and a high end, water will naturally gravitate to the low area. As a result your coils will now be constantly sitting in water. This is a prime breeding ground for mold; Mold needs water and organic food (dust) to thrive, both of which you have. In addition to the dusty/moldy coils, this standing water will naturally migrate throughout the ductwork with the airflow; Unfortunately the mold spores will also get blown throughout the house.
When you hire Advanced Furnace to come do a normal duct cleaning, the evaporator coil is blown out as part of the process. The coil is in the trunk line near the furnace and this is vacuumed out whenever we clean the duct work. We also clean all of the supply ducts, return ducts, and the blower component of the furnace. When we come to do a chemical coil cleaning (which is necessary if the coils are partially or fully blocked with pet hair and other debris), the process is a little more complex. Our service technician will access the coil in your duct work and first use a fin comb to manually comb off the coils. Next, he will use a vacuum or a high pressure air line to clean off the heavy accumulated debris. Finally he will spray a chemical cleaner directly on to the coils. This cleaner is specially formulated to dissolve dirt, hair, oils, and dust. All of these particles get caught and built up between the fins. The solvent is allowed to soak for approximately 5-10 minutes, then everything is flushed with clean water. This water will now flush easily out of the coil and drain pipe as it is designed to do. The final step of the process is a sanitizing/deodorizing of the complete system. We use a product called Oxine. Oxine is an EPA approved antimicrobial spray that kills any mold that might remain after the cleaning. It is completely safe for household use and if you were to break it down chemically it is equivalent to table salt.
When we leave your home will smell much fresher and you can be assured that the ducts and coils have been cleared of dust and debris.