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  1. #1
    Join Date
    Nov 2019
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    Considering a zoned system

    Hi, I'm a homeowner and fairly uneducated on HVAC so I appreciate any help you can provide! I'm looking to replace my HVAC system that currently serves two floors of bedrooms plus a small room that attaches to a roof deck. The current system is very basic (single stage, no zones) and it's 20 years old. My HVAC contractor recommended renovating to add one system per floor for the two bedroom floors, plus a mini-split system for the roof deck room, which benefits from heat stratification and many windows (making it very hot during the summer). Unfortunately, I can't rip up the lower bedroom floor (if I want to stay married), and there is no room for a mini-split in the roof deck room. I'm considering going with a variable speed system like the Bryant Evolution or Carrier Infinity and zoning it so each of the three floors has its own thermostat. I've read that using a bypass duct is a bad idea, and I can get around needing one by using variable speed. My contractor is not convinced though - he has had bad experience with zoned systems in the past. I'm not sure that there is another viable option though. Can you provide any reviews of the lastest zoning technology and/or recommendations on how to proceed? Thanks!

  2. #2
    Join Date
    Mar 2018
    Location
    Chico, Ca #StateofJefferson
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    His plan is the preferred method, if you have any rooms that are to hot or cold that's a ducting problem and variable speed unit may just make it worse. Zoning is a compromise and is best done during construction as the ducting must be sized to allow the proper airflow, if it's not you have a really expensive system that doesnt work well and still doesnt maintain temp. Why would you have to rip any ceiling up and why wont a mini split work?

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  4. #3
    Join Date
    Nov 2019
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    Thread Starter
    Thanks for your response Makeitcold. Right now, the lower bedroom floor is heated/cooled by two "competing" forced air systems. One comes up from the basement (I didn't mentioned this part before just to keep it simple) and the other comes down from the unit on the upper bedroom floor (the one that is 20 years old and will be replaced). My contractor recommended that I install a new unit on the lower floor and have that unit condition the lower floor only. Similarly, the upper bedroom floor would be conditioned by the replacement unit, and this unit would feed only one floor (the upper) instead of two. This would give us one unit per floor, which he said is the preferred setup. The issue with this plan is 1) I'd have to give up a closet for the lower-floor unit (and I don't have a lot of closet space), and 2) installing a unit on the lower floor would require all new duct work. Currently, there are ducts serving the lower floor from the upper floor above, and the upper floor is gutted so reconfiguring ducts for the lower floor from above would be much easier. It's an old house with a lot of detailed molding, etc. so ripping up the lower floor (which is fully intact) to add new ducts isn't an option unfortunately.

    A mini-split won't work in the roof deck room because 1) there isn't enough wall space (the room is all windows) or ceiling space for a cassette unit (the ceiling is vaulted), and 2) my wife gave this idea a hard no because she hates the way they look

    At this point I'm thinking the best bet may be to go with the contractor's idea but locate the lower-floor unit on the upper floor next to the replacement unit and feed the ducts down to the lower floor as described above. It seems silly to have two air handlers right next to each other but maybe that's the way to go. If conditioning the roof room is problematic without a mini-split, I can always use a window unit in the summer (not ideal, but would work).

    If you have any other thoughts/ideas, please let me know! Also, if we do go down the zoning path, what are the best systems? Thanks again.

  5. #4
    Join Date
    Mar 2018
    Location
    Chico, Ca #StateofJefferson
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    Why move anything? Cant the ducting to the areas you dont want to be conditioned by either system be capped? If not you'll still have to rip up ceiling to install the dampner motors. FYI daikin, Mitsubishi, etc make visible and concealed floor mount units and ducted airhandlers, they make something for everything. It's not really possible for us to see the intricacies of the job from the internet, but if the unneeded ducts can be capped you'll have to do manual j's to determine the much smaller sizes you'll need, do not let anyone install anything without manual J and D being performed or you'll end up with noisy equipment that breaks down often

  6. #5
    Join Date
    Aug 2002
    Location
    Southold, NY
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    Two floors Two Systems!

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  8. #6
    Join Date
    Nov 2019
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    Thread Starter
    Thanks for the responses, guys - much appreciated!

  9. #7
    Join Date
    Sep 2007
    Location
    State College, PA
    Posts
    2,894
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    Quote Originally Posted by pecmsg View Post
    Two floors Two Systems!
    Yes. My thoughts exactly.
    Can someone please explain to me -
    Why is there never enough time to do it right the first time, but plenty of time to do it twice?


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