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  1. #1
    Join Date
    Apr 2007
    Posts
    2

    Is this right? Vertical Duct From Crawl to Attic..

    Let me start off with a brief overview of the house. It is a 2 story with seperate split systems for upstairs and downstairs. Roof is a hip style roof. Upstairs has approximately 800 sq ft, and the house is practically square in shape. Currently the air handler and all duct work is in the attic. There are 8 registers in the ceiling with 6" metal pipe to each from the existing plenum which is at the top of the shaft I will discuss in a second. The upstairs unit recently went out. I have talked to 2 different companies that have told me two seperate things. I expressed interest in not using a split system for different reasons, but that is beside the point, but instead would like to go with a self contained package unit located outside. Approximately 8-10 feet from the outside perimeter of the house, I have a unused dead space shaft approximately 3' x 4' that runs all the way up through the house. Downstairs it is just a closet, and upstairs it is sealed off. Anyway, I expressed interest in going with the packaged unit, but wasn't sure if that was a possibility due to supply and return issues. One contractor told me that it would be tough and wouldn't really discuss any further. The other contractor told me that it could be done rather simply. He said that for the supply and return, he could run the 14" round metal duct under the crawl space approximately 8-10' and then elbow up vertically and run up through this shaft all the way to the attic. He could tie the return into the existing 12 x 20 return grill that is located on the wall of this shaft upstairs, and run the supply side on up to the plenum. He said that he would take out the entire trunk duct that is existing in the attic except for the plenum, and would run the supply lines to each register out of this. He called it a radial duct system or something like that. Does this sound right? I would really like to do this if it is right, but I once owned a 2 story home, and the upstairs system was a split system and it never worked right. Heat, high humidity, etc. I just don't want that again. I really want a outside unit. I would appreciate any thoughts you guy's have on this.

    Thanks,

    David

  2. #2
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    sounds like he is thinking and taking your concerns into acount

    he should insulate the pipes in the chase and crawl so you wont loose and temp and less chance of the pipes sweating and causing mold

  3. #3
    Join Date
    Feb 2004
    Posts
    2,597
    Why do you feel a package system will be any different than the split system?

    I would venture to say your previous split was not sized correctly or the ductwork was not properly insulated/sealed.

    If everything is properly installed and properly sized with the proper equipment, the upstairs split will perform better than any basic system. I say basic because the best seer rating you will get out of a package could be low. I can still install 10 seer package units as opposed to 13 splits.

  4. #4
    Join Date
    Feb 2004
    Posts
    2,597
    Does anyone even make a Variable Speed package resi unit?




    I just read another thread that answered my question.
    Last edited by billva; 04-03-2007 at 09:13 PM. Reason: Read another thread.

  5. #5
    Join Date
    Apr 2007
    Posts
    2

    Confused Can this be done?

    I know each of you have your different oppinions, but I don't really know anything about this. Can my original question be done? I really want your guys input on this because I don't know if this guy is jerking me around or not?

  6. #6
    Join Date
    Aug 2002
    Location
    manitowoc wisconsin
    Posts
    4,943
    A package unit has 1/3 to 1/2 of the life expectancy of a properly installed split system.It will cost you alot in the long run IMO.
    Take your time & do it right!

  7. #7
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    as long as he can get from the crawl to the attic yes it can be done

    it will work as long as it is sized and installed correctly

    manual-j and a realy good and properly designed duct system and yes it can be done if this is what you want

    the important thing is a way to run the duct work and your willingness to give up space

  8. #8
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    if you condition the upstairs & downstairs about the same temp -- then NO need to insulate the ducts thru the shaft | chase! = conditioned space. likewise for ANY ducts within any conditioned space.

    was the existing designed? or just installed?

    have you inspected the ducts in the attic?
    most issures | problems in houses are obvious to just someone looking --
    HVAC= bent & broken ducts -- big holes where branch ducts "take- off", no dampers to adjust for proper air flow to each room or all ducts of the same size with no dampers --
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  9. #9
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,296
    Can it be done? Yes.

    Would I do it if it were my house? Probably not.

    If the main objection is over a conception that a split system will not perform as well as a package system, that's a misnomer. Either system will not perform well if it is installed poorly.

    Going by your description, the long supply and return chases to go from split system to package unit will add to cost and also add resistance to the duct system.

    You could convert to a package unit and still not be happy with the performance. The most important thing you can do is insist on a properly installed system, whichever route you choose. Personally I'd stay with the split and ride herd on proper sizing, proper ductwork sizing, proper all of it installed. I would also get all ductwork sealed. The best equipmment installed poorly is worse than the bottom end equipment installed superbly...package or split.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  10. #10
    Join Date
    Dec 2004
    Location
    Derby City
    Posts
    3,958
    Doesn't much matter what we say. HE is the one who has to be sure it works to YOUR satisfaction. After all YOU"RE going to pay HIM for the work, right? If he establishes a certain expectation on your part and you are comfortable with the references and work history he has provided, then any lingering questions should be posed to him.
    Everyone has a purpose in life..........even if it's to be a bad example.

    Seek first to understand, before seeking to be understood.

  11. #11
    Join Date
    Oct 2003
    Location
    34.8n 102.4w
    Posts
    3,244

    Damn John....

    THAT is right click and save material......Perfect dude.



    Should see pages of that here.
    Life goes on long after the thrill of living is gone.

  12. #12
    Join Date
    Dec 2004
    Location
    Derby City
    Posts
    3,958
    Hey Sline, even a blind squirrel finds a nut now and again!
    Everyone has a purpose in life..........even if it's to be a bad example.

    Seek first to understand, before seeking to be understood.

  13. #13
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    It can be done. I would go with a splitthough. Use the guy who is willing to do what you, the boss, wants.
    Cem-bsee I know your not required to insulate duct in a conditioned space but IMO its a bad idea. Ive had to go back on jobs where ducts in conditioned spaces were dripping like an english ho. What if H.O. goes on vacation and turns stat way up? When he returns and sets it back to 70 those pipes are gonna pour. And to what avail, 50 bucks worth of insulation?

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