Guest guest Posted February 1, 2011 Report Share Posted February 1, 2011 Where is the plenum Gil? > > > Hi Kathy, > > I have found your letters interesting, starting with the window issue, progressing to the ducts. I wonder if the ducts are the problem, and not the windows. New windows seal far better than the old, and thus amplify any indoor air quality problems you might have. > I am really curious about the duct sealing you are mentioning. Why is it recommended? Ducts can be a big problem if old and leaky, or simply if not properly installed. Attic flex duct gets very hot in summer, and the inner plastic lining can degrade. Sealing is not the answer. Replacement is. Also, does this system have a plenum made of fiberglass ductboard, or have some other type of inner fibrous insulation? If so, replacement of the plenum is highly suggested. Sheet metal plenum and ducts are suggested, possibly with a little flexduct at the ends to connect to existing registers. All insulation should be on the outside of ducts. For extra protection against biofilm formation, you might want to pay the added cost for AK Steel's Agion Technology metal ducts. > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 1, 2011 Report Share Posted February 1, 2011 Hi Gil- Thank you so much for posting and I know, I am just all over the place...lol.... Using my existing ductwork with whatever erridication method we chose, it would reduce one more new material for the MCS to content with. So if possible, I requested options using the existing ductwork either through the furnace or as a tie in. So my HVAC guy insisted on knowing the status of my ducts. So did duct testing, found leaks particularly on the supply side. Thus his recommendation to consider sealing. His thoughts were if we were going to use the ducting for any air exchange method, we needed unleaky ducts particularly on the supply side. I would love to replace the ducting with hard ducting but other than a major construction project of running them on the interior walls then boxing them in, it's not feasible with the layout of this house. Have a very quirky home and except for a few short runs that are in open attic, there was no option but to use flex duct. To be honest, the previous owner had the retrofit done and I am amazed at how they were able to snake such long runs in between the attic floors and downstairs ceilings. As far as the plenum..yes, everything is metal. And one of the first things I did when I bought this place was have them box in/seal all the returns, which several are located on the upper outside wall that is actually located mostly above the garage. That in itself made a huge difference as when the next door neigbors have their driveway sealed, the vapors now have a harder time migrating into my house. You bring up replacing the flex duct due to potential degrading and I couldn't agree more. Am interested to know if you have any recommendations for a quality flexible ducting that might also be less toxic? My furnace and ducting are around 15 years old. Ugh, I made it through the insulation but new ducting, oh boy...lol... When Bower built/wrote the Healthy House books, he used hard ducting and I don't think he referenced less toxic flexible brands. I'll check them again though to be sure. I would sure appreciate your feedback on why you think so highly of AK Steel's Agion Technology metal ducting? I see that they are using the silver based anti-microbial compound technology and wonder if you know it's true effectiveness? I have several MCS friends who have done well with silver based coatings. Please note that I have no financial or vested interest in any person, place, object or anything else mentioned in this posting. Kathy --------------------------------- Hi Kathy, I wonder if the ducts are the problem, and not the windows. New windows seal far better than the old, and thus amplify any indoor air quality problems you might have. I am really curious about the duct sealing you are mentioning. Why is it recommended? Sealing is not the answer. Replacement is. Also, does this system have a plenum made of fiberglass ductboard, or have some other type of inner fibrous insulation? Sheet metal plenum and ducts are suggested, possibly with a little flexduct at the ends to connect to existing registers. All insulation should be on the outside of ducts. For extra protection against biofilm formation, you might want to pay the added cost for AK Steel's Agion Technology metal ducts. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 1, 2011 Report Share Posted February 1, 2011 Hi Barb, The furnace has three sections. The first is the housing for the fan and filter. The second is the firebox, where gas is burned and heat is produced. The heated air goes next to the third section, the plenum, the section above the firebox where air conditioners are usually placed. The plenum is the section where all the air distribution pipes (ducts) are attached. This is the place mold is most likely to grow during air conditioning season. Ductboard or fibrous insulation inside is a great dust trap, and moisture trap, making an ideal mold garden once any antimicrobial chemicals are depleted. Sheet metal is a far better choice, with any insulation on the outside, not in the air path. Re: Duct sealing? Posted by: " barb b w " barb1283@... barb1283 Date: Tue Feb 1, 2011 12:16 pm ((PST)) Where is the plenum Gil? Quote Link to comment Share on other sites More sharing options...
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