Results 1 to 7 of 7

Thread: Duct Layout

  1. #1
    Join Date
    Mar 2004
    Posts
    171
    On new construction here in Central NJ, it is very common for a forced air HVAC system to have one system in the basement with the ducts running through the floors and/or lower walls and a furnace in the attic with ducts running through the ceiling. Is this the best way or just the most convenient? I would think that one would want heating ducts as low as possible and AC ducts to be as high as possible. One other question-is there any problem with flex duct running through an attic, or is some other ductwork preferred. Thanks.

  2. #2
    Join Date
    Dec 2005
    Location
    Cincinnati, Oh
    Posts
    5,044
    woah? what? Ahh, atleast here in cincinnati, and residential, the air conditioning and heating run in the same vents.

  3. #3
    Join Date
    Mar 2004
    Location
    CHICAGO SUBURBS
    Posts
    464
    I think you might be talking about a two story, dedicated zone system with a unit for each story. At least that is what it sounds like.
    Some people swear by me and some at me

  4. #4
    Join Date
    Mar 2004
    Posts
    171
    Sorry if the original post was unclear. I am talking about a 2 story home with a dedicated sysem for each zone, heat and AC coming out of the same vents. I guess my question is, is it best to have the upstairs unit in the attic with the ductwork running through the attic and down through the ceiling.

  5. #5
    Join Date
    Mar 2004
    Location
    CHICAGO SUBURBS
    Posts
    464
    this is the way it is usually done. It is cost efective i.e. shorter duct runs due to prospective units being close to their zones. If you were to put both in the basement,the upstairs duct runs might end up with so many turns and jogs in them to make it upstairs that you might not get any or enough air flow. even though your upper grills are cieling mounted, the duct runs will be reletively free of offsets giving you better flow. in some cases, mostly custom jobs, it is pos. to have dead spaces built into walls called a chase.then you can get a large enough trunk line to upstairs to basement install upper zone's furnace. But you'll never get a cookie cutter builder to do that for you. Hell, they seldom will use two furnaces. Bottom line you know.
    Some people swear by me and some at me

  6. #6
    Join Date
    Mar 2004
    Posts
    171
    Thank you for the advice.

    If a furnace will be in the attic, is there some reason for not using a high (90%+) efficiency unit in the attic? Is there some problem with drainage of condensation or something else? I'm trying to spec out the Rheem/Ruud 90+% Modulating Furnace, but I want to make sure I don't insist on something that will cause problems later. The winters in our part of NJ get quite cold, and I would expect the attic to be below 32 F during the winter.

    Thanks.

  7. #7
    Join Date
    Jun 2005
    Location
    Near Chicago, IL
    Posts
    3,317
    If you put a condensing furnace in an attic, you had better build out a very insulated room for the equipment and condensate drain. It will freeze, and you will be screwed.

    Same goes if you want a humidifier up there.

    Keep in mind that the lower level unit will operate more often because heat rises. The payback on a 90% unit may not make sense in an attic on a 2 system install.

    Even for an 80%, I would still build a room due to condensation issues in the summer, when the second floor AC system will run more often.

    [Edited by neophytes serendipity on 12-07-2005 at 01:03 PM]
    Proper Prior Planning Prevents Piss Poor Performance

    "There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey. It's unwise to pay too little.
    When you pay too much, you lose a little money -- that is all. When you pay too little, you may lose everything, because the thing you bought was incapable of doing the thing it was bought to do.

    The common law of business balance prohibits paying a little and getting a lot -- it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run. And if you do that, you will have enough to pay for something better."

    John Ruskin


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event