Duct cleaning has been a very hot topic of late and I want to clear up some fallacies when it comes to ductwork. Let’s start with the three basic types of ductwork you will find in your typical attic.
The most common style of ductwork you will find today is flexible duct or flex duct for short. Flex duct is an inner plastic tube supported with a spiral wire and the wrapped-in insulation. Depending on the airflow requirements, flex duct can be as small as four inches in diameter all the way up to twenty inches. Flex duct systems are very cleanable and are not susceptible to permanent damage if they get biological growth on the interior. The mold cannot penetrate the plastic so, with the proper equipment, we can clean a flex duct system without too much trouble. In the worst case scenarios we may have to change the mixing or distribution boxes that connect the ductwork together. These boxes are made of duct board also known as fiber board.
Next up we have duct systems that are constructed completely of fiber board. This was a popular application here in the late 1970’s through the mid 1990’s. Fiber board is also the go-to material in condos and apartments where round flex duct just won’t work due to space limitations. A fiber board duct system is a whole different creature and if you have biological growth or dust and dirt issues with a fiber board system cleaning is NOT an option. Any attempt at cleaning duct board will result in the surface seal getting damaged and tiny fiberglass particles will then be blown throughout the entire space.
Up until a few years ago duct board did not have any protection from biological growth and fiber board duct systems are the perfect storm when it comes to mold growth. Mold needs three things to be very happy and they are moisture, a food source and darkness. Did somebody just yell BINGO when it comes to unprotected duct board and mold? I would say yes. Today’s fiber board comes with an additional coating to prevent biological growth. The bad news is if you have old fiber board in your home replacement is going to be the best route for the ductwork. We also have a paint called Fosters 40/20 that can be applied to the interior of the old duct board to encapsulate those nasty spores, however, the mold may continue to grow underneath it and present future problems.
Finally, we have metal duct systems. Metal ducts were also very popular in the 1970’s and 80’s. If a metal duct system is in good condition it to can be cleaned with little or no trouble. The issue we run into with older metal ductwork and trying to clean it is the vibration from the cleaning can occasionally cause the duct work to literally come apart at the seams. This is why it is very important to have the ducts fully inspected before any attempt at cleaning is made. If the metal system is deteriorated and the connections are failing, duct cleaning in this case would do more harm than good. Metal duct work has fallen out of favor in residential applications due to the much higher costs to install than the go-to flex duct system.
A word of caution: buyer beware when it comes to those ads saying we will clean any duct system for $39.95!! Proper duct cleaning in the typical single family home is going to take a good half a day or longer depending on the size of the home. All the grilles need to be removed and each vent should have a vacuum with a spinning brush ran down it to get all the dust and dirt knocked loose and vacuumed away. The go to machine for duct cleaning is called a Roto-Brush and that is what we use when we come to assist with those dust and dirt issues. Back to the topic of having a duct inspection, before cleaning it is also crucial to make sure the duct connection points are still properly sealed. If the duct connections are failing and pulling in dust and dirt from the attic, cleaning those ducts makes zero sense as the dust and dirt will be back in a matter of a few weeks. If your ducts are properly sealed and you keep a good filter on the air conditioner duct cleaning is something that only needs to be done every ten years or so. That ten-year time frame is in line with how long the connection points will hold up to the heat of the attic. I hope I have cleared up some of the fallacies when it comes to cleaning your duct system.
Until next week gang, can someone please tell me how to get to Sesame Street?
House Whisperer out!!
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