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  1. #1
    Join Date
    Mar 2011
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    Zones in Existing System

    First off I'm a complete newbie to HVAC so pardon my ignorance

    I just moved into a 3 story 4 bedroom house with one gas heating/cooling unit serving the main/basement level and another unit for the top floor. The rooms are heating very unevenly (1 is very hot, 2 are very cold, 1 is about ok).
    I talked to an HVAC guy who gave me two suggestions
    1) Put simply Mechanical Dampers on the lines coming out of the Plenum to reduce airflow to the overheating room and the hall with the thermostat (allowing more air to go to the cold room).
    Q: Would it be better to put dampers on all lines (for better control in each room), pricier but long term make everything more comfy

    2) Divide the upstairs into two zones using electronic dampers and two thermostat
    Zone 1 = Bedroom 1 (400sf) + Master Bathroom (100sf) + Closet (90 sf) + Open Hall to downstairs (200ish SF)
    Zone 2 = Bedroom 2 (200sf) + Bedroom 3 (200sf) + bedroom 4 (150sf) + 2 bathrooms
    I wanted more control within the 3 bedrooms but he said considering the size if the zones were smaller the system could have issues due to too low CFM in the zones.
    Q: What other options are there? Can Mechanical dampers be put on the lines going to the 3 bedrooms to balance them better (in addition to the electronic dampers), can temperature sensors be put into the room or anything else that would achieve more control (automated or otherwise)

    Additionally are there other options that i'm unaware of

    Thanks a bunch

  2. #2
    Join Date
    Dec 2010
    The Quad-Cities area (midwest).
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    You could try to install (if there are none now) volume dampers and "balance" the airflow manually.

    Or, maybe there is an issue with the ductwork that could be the problem and some could be added.

    I went through a house under construction yesterday. The house has been sheetrocked but the furnace/ductwork hasn't been installed yet in the basement.

    I counted the returns. This system will be about 50% shout on return air.

    Note: I haven't seen the undersized ductwork yet.

    I'm talking about a brand new house. I saw a sewer pipe going through a return air (the plumber didn't have to cut a hole). I have a call into the heating inspector.

  3. #3
    Join Date
    Feb 2011
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    Alot of time your cold area's are that way do to a poor design in the current duct work. Pulling the untreated air out of the room with proper returns is always a question and if there isn't enough can it be added.
    But if your wanting a less expensive option have you considered using manual dampers on the branch lines going to the warmer areas? You could try and balance the air flow to different parts of the house without breaking the bank.
    But if your trying to decided between the mechanical dampers just remember that by adding the branch controls you can issolate particular rooms. If you zone then you have to add separate duct work to break those zones.
    Good Luck

  4. #4
    Join Date
    Mar 2011
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    Thread Starter
    I've currently gone w/Manual dampers but down the road plan to do the two zones (w/electronic dampers) and add manual dampers on the ducts coming out of that to properly balance rooms 2 through 4 (if that would work )

    Thanks a bunch for the replies

  5. #5
    Join Date
    Jul 2004
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    Despite many opinions to the contrary, zone controls for forced air systems is a bit of a science. If the company that is installing the zoned system hasn't been well schooled on zoned equipment, relief strategies, duct sizing and other needs of a zoned system, then I'd recommend not using that company. The implications are a lot more than many (including many of the zone products manufacturers) would have people believe. Manual dampers should be included on every supply branch of every system and volume dampers should be included on every system that has multiple main trunks. Proper system balancing can only be accomplished with such dampers. For a more perfect system, the same dampers should be installed on the returns. Balance is needed on both sides of the system when multiple return air routes are installed.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  6. #6
    Join Date
    Jul 2008
    Rochester NY
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    Time for an energy audit. Need to better understand how your home performs.
    Which makes more sense to you?
    CONSERVATION - turning your thermostat back and being uncomfortable. Maybe saving 5-10%
    ENERGY EFFICIENCY - leaving your thermostat where everyone is comfortable. Saving 30-70%

    What is comfort? Well, it AIN'T just TEMPERATURE!

    Energy Obese? An audit is the next step - go to, or RESNET, and find an auditor near you.

  7. #7
    Join Date
    Apr 2011
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    Where is the thermostat in relation to the affected areas? Maybe I'm oversimplifying, but it could be a matter of turning the fan to the "on" position? I know it is in my own home.

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