In one of my previous blogs, we did the 10,000-foot view of an HVAC system and I explained the basic components: the furnace, air conditioner, and heat pump, and when and how they go together. The next part is how the air gets out of those pieces and into your house – the ductwork. For most people it’s out of sight, out of mind. Not many people are excited by the thought of crawling around a crawlspace or taking a walk around the attic on any sort of a regular basis to look at the spider web mess of silver running everywhere. But sometimes the reason you may feel more heat in one room than another, or one side of the house may be cooler than the other, isn’t because there’s anything wrong with your equipment. There’s something wrong with the ductwork.
Leakage from Damaged Ductwork or Poor Connections
Over time things can happen to ductwork. The house may have settled. Age and environmental conditions take their toll. The creepiest may have happened – a critter or rodent of some sort thought it looked like great construction material, found out it was warm inside that shiny tube, and took up residence. Or at least disassembled part of it to go make its own home somewhere else. What’s left is a hole. Turn on the air conditioner and you’re now cooling your attic or crawlspace. Same with the heat. Ultimately it means you’re paying to heat and cool the outside. Good luck with that one.
Besides holes, ductwork can fall off the “boot” which is the metal piece inside your register. This is more common when the ductwork is located in the crawlspace or basement. Gravity takes its toll, or it accidentally gets pulled off when someone crawls past to pull out the swimming pool for the kids. In attics it’s crushed ductwork that can be a problem. The cable guy has to run cable in the attic and accidentally steps on a duct while performing a precarious balancing act. Or in the process of putting the Christmas stuff away, a box falls on a duct run. Now all the air that’s supposed to be coming out of that line has been cut off and isn’t making it into your home. (That creates a whole list of other problems but I won’t go into those here. Suffice to say it’s bad.)
And in both attics and crawlspaces we find problems with our nemesis in the HVAC business: duct tape. Remember this: duct tape is for everything BUT ducts. It can not hold up under the heat, the cold, and the humid conditions ducts typically see and quickly falls off. You will see tape on the equipment sometimes, and it’s usually used to hold insulation on ductwork, but this is special tape designed for this very purpose, approved by scientific labs for this application, required by building codes and it costs a fortune. It can not be replaced by the old gray standby, no matter how many colors it comes in these days. (Leopard print? Really?)
Repairing this kind of damage is not as simple as it seems. There is more to the construction of a duct than just shiny silver stuff and insulation. It’s also possible that a poor repair job can cause damage further up the line including to the equipment itself. Only a qualified HVAC contractor is going to be able to determine the extent of the damage and repair it properly.
Mold
Unfortunately, mold, mildew, and bacteria can grow in ductwork. Since you just read “Leakage From Damaged Ductwork or Poor Connections” above you know how this can happen. Mold and mildew thrive in wet locations. Add a little heat and a food source and you have all the makings of health issues and poor indoor air quality. Please read this part carefully: if your ducts are constructed of ductboard, which is typically silver with a quilted pattern on the outside and yellow pressed insulation on the inside, IT CAN NOT BE EFFECTIVELY CLEANED. Even the EPA agrees (http://www.epa.gov/iaq/pubs/airduct.html). Ductboard can not be cleaned of mold. Ductboard can’t even really be cleaned of dirt and debris. Mostly all that a cleaning does is break loose those fiberglass insulation particles and sends them into your house. But if your ductwork is metal and isn’t lined on the inside, it CAN be cleaned of mold. Dirt and debris too but that shouldn’t be necessary. If you have a lot of dirt and junk in your ductwork, you need a professional to find the source first before you get it cleaned. That shouldn’t be happening.
I need to interject another little lesson in ductwork construction. The long, usually rectangular or square runs are called trunk lines, trunks, or plenums. The soft, round silver lines coming off the trunk are typically constructed of a material called flex, for flexible duct. Flex also can not be effectively cleaned. If there’s a mold problem, the flex should be replaced. Don’t let anyone tell you differently.
This is getting a little more in-depth than I planned to go in this article but I think it’s important for you to know. Ducts are complicated. For as simple as they look, there’s a lot of science behind their construction, their function, their installation and even their size. If you suspect mold, the first thing you need to do is call a qualified mold remediator like ServPro of Hickory. If they confirm that it’s mold (and only testing in a lab can confirm that), then call a well-qualified, licensed HVAC contractor and have your ducts fixed. This is a serious health problem and needs to be dealt with by professionals.
Missing Insulation
Ductwork is insulated. Besides helping more of the air you’re paying to heat and cool stay warm or cold until it hits the right room, it also stops your ductwork from dripping condensation. Condensation is moisture and moisture in the wrong place does all kinds of damage (see what mold needs to grow, above.) The insulation is also an energy saver. Sorry to repeat myself again, but if you spot torn insulation, call your HVAC contractor. Depending on the extent of the tear and the location, the problem may be more than just torn insulation and only an HVAC contractor can tell you that for sure.
So now you know – there’s more to it than meets the eye. If you have any questions at all or think you may have duct problems, please feel free to call me, Craig, at 828-327-9680. I love ductwork! (Seriously, I do.)
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Do you need to have your duct system inspected? Call Canella Heating & Air Conditioning! For over 20 years, Canella Heating & Air Conditioning has been providing Hickory, Newton, Conover, Granite Falls, Hudson and the surrounding areas with the highest quality HVAC products and the most outstanding customer service available — winning numerous awards along the way. Call Canella today and start enjoying your air! 828-327-9680 or check out the website at www.canellaheatingandair.com.






