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  1. #1

    Duct Work cleaning or total replacement?

    I'm sure this has been asked before but I have a specific situation. My duct work is nasty dirty; not filled with mouse droppings or anything, just a little moldy and really dusty. A rough estimate to clean them is about $1000 but they're going to do more than just clean the ducts, they'll clean the blower and coil and I don't want that. The unit itself was thoroughly cleaned last year.

    I can do 90% of home repair/remodeling myself, including plumbing, electrical and carpentry. I've never truly tackled something like this but I can learn anything.

    So the question is, with a roughly 1100 sq. ft. home, 1 unit, 1 return and all ducts located in a spacious crawl space, is it worth it for me to disconnect and pull out all the duct work one by one and clean it myself or just place all of it? I'm also a stingy person, so if I can save $100 by replacing all of it then I will.

  2. #2
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
    Posts
    3,298
    it depends on what kind of ductwork currently in the house.
    insulation cannot be put back on (and new insulation is higher quality, so you really wouldn't want to)
    flex ducts often cannot be cleaned, they must be replaced. there are a LOT of codes surrounding ductwork, involving their routing, the fittings, the size and the length.
    I've never seen ductwork that would benefit from cleaning vs outright replacement, but if you have a proper plenum/take off system currently, and it's full of dirt, then removal, cleaning and PROPERLY REINSTALLING with duct sealant on each joint and seam. and insulating with R8 properly installed by the insulation manufacturers recommendations... that would be OK.
    The TRUE highest cost system is the system not installed properly...
    The three big summer hearththrobs...
    Mel Gibson
    Dwane Johnson
    The A/C repairman

  3. #3
    Excellent. And I would replace it in the same fashion that it was installed. It's not that old, only about 15 years and I wouldn't try to change the route or do anything weird. I'll just read up on it and decide whether or not I should do this myself, or have someone else do it.

  4. #4
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
    Posts
    3,298
    I do not recommend reconnecting the ductwork the same way the original was installed, same routing, sure, but current assembly methods are far superior to old ones.

    keep in mind, ductwork assembled prior to the mid 70's was sealed with asbestos tape... and I DO NOT recommend anybody attempt that job...
    The TRUE highest cost system is the system not installed properly...
    The three big summer hearththrobs...
    Mel Gibson
    Dwane Johnson
    The A/C repairman

  5. #5
    No this house was built around 1995. And I do a full amount of research on something that I don't know before taking on a project like that. And all I meant was that I won't do major modification to the original duct work design. I'm not moving vents or moving the entire unit, just updating the duct work so to speak.

  6. #6
    Join Date
    Jun 2002
    Location
    Dacula, GA
    Posts
    12,725
    Quote Originally Posted by gertnerbot View Post
    No this house was built around 1995. And I do a full amount of research on something that I don't know before taking on a project like that. And all I meant was that I won't do major modification to the original duct work design. I'm not moving vents or moving the entire unit, just updating the duct work so to speak.
    Well to begin with you can clean your own duct by just installing filters in the diffusers and replacing as need and taking them out when they blow clean for a while.

    Don't ever assume your duct was installed correctly because most are undersized and if flex are compressed and restricts your air flow to much. If you want to check then get a ductulator and assume 400 CFM per ton of cooling and don't go higher than a 0.06" /100' of duct fiction loss to figure your cfm per duct and see if the duct is adequate and if not get an installer to put the correct duct in right.
    "I could have ended the war in a month. I could have made North Vietnam look like a mud puddle."
    "I have little interest in streamlining government or in making it more efficient, for I mean to reduce its size. I do not undertake to promote welfare, for I propose to extend freedom. My aim is not to pass laws, but to repeal them. It is not to inaugurate new programs, but to cancel old ones that do violence to the Constitution."
    Barry Goldwater

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