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Duct Cleaning 101

Duct Cleaning 101
Reading Time: 4 minutes

“Do You Guys Clean Ducts?”

This is a very common call coming into our call center and of course the answer is yes. The first thing we need to do is to set up a duct evaluation. “Why do you have to evaluate my ducts? I just want you to come clean them,” is usually the next thing out of the client’s mouth.

Let’s take a deep dive into duct work and the types of duct systems that are out there in our market. I will do my best to answer the question as to why ducts need evaluation as well as exploring different types of cleaning and even sealing processes for duct work. I want to start with the types of duct work and go from there. We typically find three kinds of duct work in our homes here in South Florida.

  • Flexible Ducting
    Also known as flex duct for short. Flex is a plastic tube that is reinforced with a spiral wire and then the tube is insulated on the outside with batted fiberglass and the last layer of insulation is a foil type of product to reflect heat away from the duct. This type of duct is very cleanable and will typically last +/- 30 years in an attic environment. Flex duct is the most common application used in homes built from the 1990’s going forward.
  • Duct Board
    Duct board, also known as fiber board, is very similar to a sheet of drywall in that it comes in 4’ x 8’ sheets that are cut to form, boxes, rectangles, triangles – whatever shape we need to make the duct system. Fiber board is also used as connection points for flex ducts. You can have a duct system that is fully made of fiber board, however the more typical application is a combination of flex and duct board. Again pre-1990 or so duct board had a huge disadvantage. The industry at the time failed to realize that mold needs three things to be very happy; moisture, darkness, and a food source. Old fiberboard systems are often full of biological growth that cannot be cleaned. If your home was built before 1990 and you have a full fiber board system, replacement is really the only option – Sorry. Even in newer systems trying to clean duct board is not recommended as you can disturb the surface that seals the fiberglass all together and end up blowing fiberglass particles throughout the space.
  • Metal Ducting
    Metal ducts are just what they sound like, sheet metal in a variety of shapes such as round, square, rectangular and even spiral can be found in some commercial applications. Next time you are in a sports bar or a brew house look up you will likely see spiral ducting. Metal ducts are very cleanable depending on age. In homes that were built from the 1960’s through the 1980’s is where you will most likely find metal ducting. The reason I say metal ducts are cleanable hinging on age is if the ducts are more than 30 years old they are going to be very rusted and in poor condition after that many years in the attic. The cleaning process could result in the duct work falling apart and that would not be a good thing.

Okay, that’s the types of duct work you’ll find in a home, so what about cleaning processes? First, beware the newspaper flyer that says we will clean your duct system for only $9.95 per vent. The old-adage of if it sounds too good to be true it is just stood up and waved a big red flag at you. From what I know about these types of companies they take down the grilles and stick a vacuum cleaner up the duct about two feet and call it cleaned. Uh… no, that is not a duct cleaning.

Duct work lines are at a minimum 5 feet long and can be as long as 30-40 feet depending on the duct system configuration. Specialized machinery such as a Roto-Brush system is required to properly clean ducts. There is also another method that involves a 20 HP vacuum with a 6” hose and a brushing system to really clean the duct system up.

How often do I need to clean my ducts you ask? The answer depends on you. If a duct system is properly sealed and you keep good filters on your air conditioner the answer is maybe every 5 years or so. If you are bad about filter changes, have a lot of pets in the home, have done major construction or have had a mold problem then cleaning more often may be required. This is where I’m going to point you right back to the duct evaluation to really answer the question.

One final note – cleaning your duct work without making sure it is properly sealed makes as much sense as getting your four-wheel drive truck completely detailed and five minutes later going four wheeling in the Everglades! Duct work that is not properly sealed will just pull dust, dirt, mold, pollen and allergens into it from the attic space in which it lives.

Alright, I am off to see why Mrs. Haywood’s master bedroom is 5 degrees hotter than the rest of the house. Until 604,801 seconds tic off the clock and we are back together, I got home the other day and thought about doing nothing until I realized I did know when I’d be done…

House Whisperer out!!


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