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  1. #14
    So in your opinion, is the solution a 3-ton "standard speed" system, or a larger (3.5 or 4 ton) variable speed system?

    Either way, I find it interesting that my old 3 ton system used to get the humidity down to 45% in my house on the wettest hottest day. Yet this new 4-ton Trane system, no matter how long I run it, even if it runs nonstop for 3 hours, the humidity never goes below 56%.

    I must be an idiot: How is it possible that a newer, more powerful machine dehumidifies LESS than an old smaller machine, if they are both run for the same amount of time? Are you guys saying that a 4-ton machine sucks less moisture out of the air in one hour, than a 3-ton machine in the same hour (amount of time)?

  2. #15
    Join Date
    Jun 2006
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    Quote Originally Posted by hortenserogers View Post
    So in your opinion, is the solution a 3-ton "standard speed" system, or a larger (3.5 or 4 ton) variable speed system?

    Either way, I find it interesting that my old 3 ton system used to get the humidity down to 45% in my house on the wettest hottest day. Yet this new 4-ton Trane system, no matter how long I run it, even if it runs nonstop for 3 hours, the humidity never goes below 56%.

    I must be an idiot: How is it possible that a newer, more powerful machine dehumidifies LESS than an old smaller machine, if they are both run for the same amount of time? Are you guys saying that a 4-ton machine sucks less moisture out of the air in one hour, than a 3-ton machine in the same hour (amount of time)?
    It's not that....the bigger more powerfull machine doesn't run long enough to remove the humidity. From your earlier post, 3 tons was pretty close to the perfect size...however...even if you got a 2 stage system you would probably be in the same situation at 4 tons.

    I don't like the 2 stage systems that only run at 80% of full stage... so in your case if you got a 2 stage 80% of 4 tons is 3.2 tons and would almost be perfect running on low stage for your house forever= waste of money.

  3. #16
    Join Date
    Jun 2005
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    SW Wisconsin
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    Quote Originally Posted by hortenserogers View Post
    So in your opinion, is the solution a 3-ton "standard speed" system, or a larger (3.5 or 4 ton) variable speed system?

    Either way, I find it interesting that my old 3 ton system used to get the humidity down to 45% in my house on the wettest hottest day. Yet this new 4-ton Trane system, no matter how long I run it, even if it runs nonstop for 3 hours, the humidity never goes below 56%.

    I must be an idiot: How is it possible that a newer, more powerful machine dehumidifies LESS than an old smaller machine, if they are both run for the same amount of time? Are you guys saying that a 4-ton machine sucks less moisture out of the air in one hour, than a 3-ton machine in the same hour (amount of time)?
    How low was the SEER on the old 3-Ton? Those lower SEER units had larger capacity compressors & would pull the evaporator temp & pressure down lower resulting is a colder coil which helps increase condensation.

    Additionally, I'm thinking the 4-ton may not be properly setup to do its most effective job of dehumidification.

    At what point are you or your system reading the humidity on the new unit compared to where it was taken on the 3-Ton?

    Was the duct system modified 'in any way' from what it was with the 3-Ton?

    Even run the same length of time, the 4-Ton will pull the temp down faster & lower air temperatures result in higher % humidity readings; even if the 4-Ton condensed slightly more moisture from the air during that same runtime.

  4. #17
    I am reading the indoor humidity with a digital hygrometer, which is the same hygrometer I had before when the 3-ton was in the house. I am reading the levels after the new 4-ton unit has been on nonstop for two hours. I used to watch the humidity levels in the house and with the old 3-ton they were always at 45-50%. The only time this was not the case was when I had the AC off and the windows open.

    In addition, it is very easy to detect high indoor humidity levels, without a gadget. You can feel it everywhere, see it in your salt jar, feel it on the carpet, etc. With my old 3-ton unit, I never had these issues.

    They did not do any duct work, other than replacing that duct/box that goes from the air handler into the ceiling (the main feed into the ducts in the attic).

    They have already come out to lower the fan speed in the 4-ton, and that is not helping the humidity situation.

    At this point I have two options: Ask them to put my old 3-ton unit right back where they found it, or replace the 4-ton Trane unit with a 3-ton Trane unit. But now I am completely traumatized and am hoping and praying that the new Trane 3-ton will dehumidify as well as my old one did. If it's not going to dehumidify as well as the old one did, then I need to go with a different brand/model/etc. Indoor humidity above 50% is NOT ACCEPTABLE to me. It is better to be warm and dry (old unit), than to be cold and clammy (new unit).

    The old system: I do not know what the SEER was. It was installed in the mid-2000s and the brand is Arcoaire (a/handler) and Tempstar (condenser). If you are wondering why I replaced, it's because the bedrooms were hot and their solution to that was: get a 4-ton.

    I don't know if this makes any sense: But, the air coming out of the new 4-ton unit is VERY cold, but clammy. The air coming out of my old unit was not as cold, but DRY. Does that make sense to anyone here????

  5. #18
    Join Date
    Feb 2009
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    Tallahassee, FL
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    What if your old unit wasn't really performing 3 tons? Or inside unit was 3 tons and outside was 2.5? Basically blowing warmer air- and running near constant as you describe. And you had return problems because they at least did add one of those. Now you have brand new big boy 4ton single stage unit blowing twice as much air. And its cold. Probably slightingly too cold.

    What I'm getting at is all too often people ask me for a bigger unit because theirs isn't working well and they want bigger because it never gets below 77.

    IMO....you scared the contractors into not wanting you to call them and say its still 77 and running all the time.

    Not saying you are to blame just think I know what happened.

  6. #19
    Join Date
    Feb 2009
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    Tallahassee, FL
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    Oh and you should scare them by asking to have your old unit back.


    Because it was probably destroyed. Hey even I don't gingerly remove them.

  7. #20
    Join Date
    Nov 2004
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    SW FL
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    Quote Originally Posted by hortenserogers View Post
    I am reading the indoor humidity with a digital hygrometer, which is the same hygrometer I had before when the 3-ton was in the house. I am reading the levels after the new 4-ton unit has been on nonstop for two hours. I used to watch the humidity levels in the house and with the old 3-ton they were always at 45-50%.

    In addition, it is very easy to detect high indoor humidity levels, without a gadget.
    You can feel it everywhere, see it in your salt jar, feel it on the carpet, etc. With my old 3-ton unit, I never had these issues.

    They have already come out to lower the fan speed in the 4-ton, and that is not helping the humidity situation.

    At this point I have two options: Ask them to put my old 3-ton unit right back where they found it, or replace the 4-ton Trane unit with a 3-ton Trane unit.

    But now I am completely traumatized and am hoping and praying that the new Trane 3-ton will dehumidify as well as my old one did. If it's not going to dehumidify as well as the old one did, then I need to go with a different brand/model/etc.

    Indoor humidity above 50% is NOT ACCEPTABLE to me. It is better to be warm and dry (old unit), than to be cold and clammy (new unit).

    The old system: I do not know what the SEER was. It was installed in the mid-2000s and the brand is Arcoaire (a/handler) and Tempstar (condenser).
    If you are wondering why I replaced, it's because the bedrooms were hot and their solution to that was: get a 4-ton.

    I don't know if this makes any sense:
    But, the air coming out of the new 4-ton unit is VERY cold, but clammy.

    The air coming out of my old unit was not as cold, but DRY.
    Does that make sense to anyone here????
    The COIL leaving Air Temperature must be 54'F or less to achieve < 47% Relative Humidity (R.H.). at 75'F
    The air coming off any coil is > 90% R.H.

    http://www.thermalinc.com/math/wetbulbcalc.htm
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  8. #21
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,120
    Quote Originally Posted by hortenserogers View Post
    So in your opinion, is the solution a 3-ton "standard speed" system, or a larger (3.5 or 4 ton) variable speed system?

    Either way, I find it interesting that my old 3 ton system used to get the humidity down to 45% in my house on the wettest hottest day. Yet this new 4-ton Trane system, no matter how long I run it, even if it runs nonstop for 3 hours, the humidity never goes below 56%.

    I must be an idiot: How is it possible that a newer, more powerful machine dehumidifies LESS than an old smaller machine, if they are both run for the same amount of time? Are you guys saying that a 4-ton machine sucks less moisture out of the air in one hour, than a 3-ton machine in the same hour (amount of time)?
    When the 4 ton unit runs 1 hour. It makes the house cooler then the 3 ton did in 1 hour. Which requires far more moisture to be removed per hour to get/keep the RH down. The 4 ton is simply cooling the house to quick.

    Under the conditions that your old 3 ton ran 1 hour to maintain temp. Your new 4 ton probably only has to run 40 minutes to maintain that temp. But in that short 40 minute run time it can only remove about 85% as much moisture as the 3 ton would in 1 hour.
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  9. #22
    Join Date
    Jun 2005
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    SW Wisconsin
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    Quote Originally Posted by hortenserogers View Post
    I am reading the indoor humidity with a digital hygrometer, which is the same hygrometer I had before when the 3-ton was in the house. I am reading the levels after the new 4-ton unit has been on nonstop for two hours. I used to watch the humidity levels in the house and with the old 3-ton they were always at 45-50%. The only time this was not the case was when I had the AC off and the windows open.

    In addition, it is very easy to detect high indoor humidity levels, without a gadget. You can feel it everywhere, see it in your salt jar, feel it on the carpet, etc. With my old 3-ton unit, I never had these issues.

    They did not do any duct work, other than replacing that duct/box that goes from the air handler into the ceiling (the main feed into the ducts in the attic).

    They have already come out to lower the fan speed in the 4-ton, and that is not helping the humidity situation.

    At this point I have two options: Ask them to put my old 3-ton unit right back where they found it, or replace the 4-ton Trane unit with a 3-ton Trane unit.

    But now I am completely traumatized and am hoping and praying that the new Trane 3-ton will dehumidify as well as my old one did. If it's not going to dehumidify as well as the old one did, then I need to go with a different brand/model/etc. Indoor humidity above 50% is NOT ACCEPTABLE to me. It is better to be warm and dry (old unit), than to be cold and clammy (new unit).

    The old system: I do not know what the SEER was. It was installed in the mid-2000s and the brand is Arcoaire (a/handler) and Tempstar (condenser). (Probably a 10 or 12-SEER) If you are wondering why I replaced, it's because the bedrooms were hot and their solution to that was: get a 4-ton. (There solutions were not the best solutions if you wanted to keep humidity low).

    I don't know if this makes any sense: But, the air coming out of the new 4-ton unit is VERY cold, but clammy. The air coming out of my old unit was not as cold, but DRY. Does that make sense to anyone here?
    Believe me I feel your traumatized frustration; when you make a big investment you expect a good result. This is why it is extremely important for the contractor to discuss the negative effects on humidity levels that up-sizing too much can cause.

    As contractors our central objective should always be to satisfy the COMFORT & the efficiency requests of the customer; never ever the profit motive over-kill sizing scenarios.

    That is also why contractors need to learn how to do Home Energy Efficiency Audits &, do room by room load calcs.

    The home often needs to be modified as a key part of the duct system & a key part of the heating & cooling system.

    That is why for both comfort & efficiency, Id rather have a system slightly undersized than oversized.

    Your situation could have & should have been avoided with a careful evaluation of all of the key factors of importance to you.

    As DAN SW FL said, the SA coming out of the registers will normally be >90% & above; however, the colder air coming from the 4-Ton maybe slightly higher in humidity & being much colder will feel clammier.

  10. #23
    Join Date
    Mar 2009
    Location
    Mount Holly, NC
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    3,192
    for humidity control, size is NOWHERE near as important as airflow!
    the ductwork needs to be sealed tight, and insulated properly. most florida systems I've run across are either in the concrete slab, or in the attic. obviously, if the ducts are in the slab nothing can be done to improve the ducts aside from having them cleaned.
    if they are in the attic, they can be mastic sealed on every seam, and insulated with modern R8 insulation PROPERLY installed. also, the resistance and layout can be improved for proper distribution to the entire house. zoning is another option for a larger ranch style home.
    I'm totally amazed all the contractors recommended a 4 ton system in florida, where HUMIDITY is the major concern.
    I would have recommended ductwork replacement, if the original system was functioning, but not getting all the rooms as needed. likely all that was needed was a large return closer to the warm rooms, or simply tightening up the seals on the existing runs...
    The TRUE highest cost system is the system not installed properly...
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  11. #24
    Thank you all for your help and guidance.

    As I begin the task of resolving this issue, I have just one final question: If a smaller unit removes humidity best, but a larger unit cools the home the best, how exactly do you arrive at a happy medium? I guess by doing a load calculation? (which my guy never did).

    I am hoping that replacing the 4-ton Trane with a 3 ton Trane will remove humidity like my old unit did, and yet possibly cool the house a tad bit better. But I am not willing to sacrifice humidity control for more cold air. Excess humidity causes way too many problems.

    I wish the contractor would have done many things, but most important: I wish he would have told me that going to a larger machine was going to affect my indoor humidity. If he would have told me that, I would have canceled the whole thing and done further research.

  12. #25
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    Arnold mo
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    An answer without a question is meaningless.
    Information without understanding is useless.
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  13. #26
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    Nov 2004
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    SW FL
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    Psychrometric Rules

    Quote Originally Posted by udarrell View Post

    That is why for both comfort & efficiency, Id rather have a system slightly undersized than oversized.

    Your situation could have & should have been avoided with a careful evaluation of all of the key factors of importance to you.

    As DAN SW FL said, the SA coming out of the registers will normally be >90% & above; however, the colder air coming from the 4-Ton maybe slightly higher in humidity & being much colder will feel clammier.
    I would have to say that the NEW coil has a slightly higher temperature and humidity with respect to the return air.
    The air flow from the 4-ton could actually be 30%_or_more greater than the 3-ton.

    I would think that the air directly at the downstream side of the coil is > 57'F, Not 52'F, if the house air is 75'F and > 56% R.H.
    Otherwise, the physics doesn't seem to work IMO.
    Or there's something, like a pool or several aquariums, generating a lot of moisture inside.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

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