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  1. #1

    zoned air condition system

    i am getting ready to install a new air condition system. i want a zoned system. first floor one zone and the second floor another. so my question is can i run 2 air handlers off of 1 condenser or do i need one for each air handler? i will have an air handler in the attic for the second floor and one in the basement for the first floor. thanks.

  2. #2
    Join Date
    Mar 2005
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    burlington county n.j.
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    Quote Originally Posted by woodvette View Post
    i am getting ready to install a new air condition system. i want a zoned system. first floor one zone and the second floor another. so my question is can i run 2 air handlers off of 1 condenser or do i need one for each air handler? i will have an air handler in the attic for the second floor and one in the basement for the first floor. thanks.
    do it with 2 outdoor units.
    it could PROBABLY be done with 1 but they're not really designed for it.
    2 units will give you a cool place to hide out if 1 zones goes down for some reason.

  3. #3
    Join Date
    Mar 2013
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    Joplin,Missouri
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    I'm not sure you understand what a zoned system is. In your instance a zoned system would be one air handler and one condenser that use zone dampers in the ductwork to control the temp in 2 different areas independently. 2 air handlers and 2 condensers would just equal 2 desperate split systems.

  4. #4
    Join Date
    Mar 2013
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    Joplin,Missouri
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    That should have said two different split systems. Damn auto correct.

  5. #5
    Quote Originally Posted by brian.cornell View Post
    I'm not sure you understand what a zoned system is. In your instance a zoned system would be one air handler and one condenser that use zone dampers in the ductwork to control the temp in 2 different areas independently. 2 air handlers and 2 condensers would just equal 2 desperate split systems.

    so i should just do 2 separate split systems then. ??
    i don't have an easy way to have the duct work for the first and second floor connected to 1 air handler. and from what i am reading i have to have to have a outdoor unit for each air handler.

  6. #6
    Join Date
    Mar 2013
    Location
    Joplin,Missouri
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    That's probably what I would do if I were you. Call a reputable company that gives free estimates to come out and look at it and go over all the options with you.

  7. #7
    Join Date
    May 2004
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    south louisiana
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    or use one unit with multiple thermostats. that is a zoned system.
    motorizd dampers that open & close as determined by each tstat.

    understand that you have several things to think about.
    with one unit zoned...
    ducts are sized for the unit size you have currently (hopefully)
    you'd need a zone system. motorized dampers, control board & tstats.
    usually each floor is broken into at least two zones.

    with two units.
    tear out of ductwork that currently serves whole house via one unit.
    new lines, new electrical etc for new unit, plus replacement of
    existing unit with smaller unit.
    twice the equipment cost
    heck of a cost for tear out and 2 new duct systems.
    cost to maintain two units.

    only hire a company that has proven experience with zoned
    systems. you don't want to be anyone's learning curve.
    you'll quickly learn that the old saw about having a warm/cool
    place to go with two units is a line used by folks who can't do
    true zoned systems...that is how it is here.

    if a company invests in educating themselves in zoning,
    they will be quick to come when you call.

    a true zoned system is great when it is installed correctly.
    living room dining tstat can be set to run less
    when bedrooms are in use.
    and then switch over if you'd like when the bedrooms aren't in
    use.
    you decide by setting temps on tstats for the comfort that
    serves your family best.

    best of luck.
    The cure of the part should not be attempted without the cure of the whole. ~Plato

  8. #8
    Join Date
    Apr 2012
    Location
    Texas
    Posts
    196
    The problem I find with zoned systems is, to troubleshoot one usually takes any contractor a long time to figure out because no one diagrammed the install. (looked at a Honeywell two zone system today - 5 years old - no documentation anywhere on the internet to diagnose the equipment - I'm quoting a new control unit and controller.) There are many systems and when the guy who puts yours in leaves town, you get to look around and find another zoned system installer. On the plus side with a two zone system and dampers, you can put in a single condenser with a two stage compressor (or even a two compressor condenser) combined with a single air handler that has a variable speed inside blower and get more savings. But as I say, finding someone who can just rush out and fix it when it goes haywire isn't easy.
    Economy - Quality - Speed <---- pick two

  9. #9
    Quote Originally Posted by energy_rater_La View Post
    or use one unit with multiple thermostats. that is a zoned system.
    motorizd dampers that open & close as determined by each tstat.

    understand that you have several things to think about.
    with one unit zoned...
    ducts are sized for the unit size you have currently (hopefully)
    you'd need a zone system. motorized dampers, control board & tstats.
    usually each floor is broken into at least two zones.

    with two units.
    tear out of ductwork that currently serves whole house via one unit.
    new lines, new electrical etc for new unit, plus replacement of
    existing unit with smaller unit.
    twice the equipment cost
    heck of a cost for tear out and 2 new duct systems.
    cost to maintain two units.

    only hire a company that has proven experience with zoned
    systems. you don't want to be anyone's learning curve.
    you'll quickly learn that the old saw about having a warm/cool
    place to go with two units is a line used by folks who can't do
    true zoned systems...that is how it is here.

    if a company invests in educating themselves in zoning,
    they will be quick to come when you call.

    a true zoned system is great when it is installed correctly.
    living room dining tstat can be set to run less
    when bedrooms are in use.
    and then switch over if you'd like when the bedrooms aren't in
    use.
    you decide by setting temps on tstats for the comfort that
    serves your family best.

    best of luck.
    i actually do not have any duct work now. it is an old house that never had ac or ducts. my heat is baseboards. so now is the time to get it the way i want it.
    thanks for replying.

  10. #10
    Join Date
    Jan 2009
    Location
    Keokuk, IA
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    5,520
    Best option then is 2 systems. Better to spend extra and get more comfort than figure out how ot run duictwoork between the floors.

    Try to avoid installing the equipment in the attic or putting the ductwork there either if you can sacrifice a central closet. Any ductwork you place in the attic needs ot be very well insulated and completely air tight.

    At minimum give up some space and make a central utility closet to put the unit in, then use a central return and make sure you doors are undercut at least 1" to get air out of the room with the door shut.

  11. #11
    Quote Originally Posted by motoguy128 View Post
    Best option then is 2 systems. Better to spend extra and get more comfort than figure out how ot run duictwoork between the floors.

    Try to avoid installing the equipment in the attic or putting the ductwork there either if you can sacrifice a central closet. Any ductwork you place in the attic needs ot be very well insulated and completely air tight.

    At minimum give up some space and make a central utility closet to put the unit in, then use a central return and make sure you doors are undercut at least 1" to get air out of the room with the door shut.
    i will go with 2 systems. unfortunately it will have to go in the attic. no place else to put the unit. yes, i had already planned to seal and insulate the ducts well. thanks

  12. #12
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,638
    Quote Originally Posted by woodvette View Post
    i will go with 2 systems. unfortunately it will have to go in the attic. no place else to put the unit. yes, i had already planned to seal and insulate the ducts well. thanks
    Ducts in the cold attic will have condensation in them during anytime the attic temperature is below the dew point of the home. Insulation alone is not a solution to the problem. You will need to circulate enough house air to keep the surface of the ducts above the dew point temperature. This is a big problem in cold climates when the homes indoor dew point is above the attic temp. We get posts about condensate in attic ducts. This results in mold in the ducts musty odors.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  13. #13
    Quote Originally Posted by teddy bear View Post
    Ducts in the cold attic will have condensation in them during anytime the attic temperature is below the dew point of the home. Insulation alone is not a solution to the problem. You will need to circulate enough house air to keep the surface of the ducts above the dew point temperature. This is a big problem in cold climates when the homes indoor dew point is above the attic temp. We get posts about condensate in attic ducts. This results in mold in the ducts musty odors.
    Regards TB
    not sure i follow you. this is strictly an AC system and the attic will be hot when the system is in use not cold. i am in maryland.
    i had a system in the attic at my last house like this an no problems.
    thnaks.

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