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  1. #1
    Join Date
    Jun 2006
    Posts
    4
    The indoor humidity in my air conditioned home as risen recently. I'm in a very dry climate (outdoor humidity in Southern AZ is about 5% right now) but noticed over the past couple of days the indoor humidity rising. Could this be caused by HVAC condenser/evaporator problems?
    Thanks!

  2. #2
    Join Date
    Dec 2005
    Posts
    4,067
    If your air conditoining is maintaining the proper temperature in your house its probably working fine. The only problem could be if the unit is oversized it might not remove the humidity fast enough. Try lowering your thermostat a little and see if that helps.

  3. #3

    Unhappy

    Originally posted by jm123
    (outdoor humidity in Southern AZ is about 5% right now)
    Do you need relative humidity lower than that?

    http://www.air-conditioner-selection...er-sizing.html

  4. #4
    Join Date
    Jun 2006
    Posts
    4
    The unit is cooling the house fine and not running any longer than it used to. The indoor humidity is a comfortable 35%, but it never used to get that high. I was just wondering if it’s normal for an HVAC system to put that much more moisture into the air.
    Thanks!

  5. #5
    Join Date
    May 2004
    Posts
    1,462
    Cooling system have no way to add moisture to the air. They normally remove moisture, but in and of themselves can not add what is not already there. In other words they can not make water. They can distribute moisture from other sources, maybe a shower fan not working, clothes dryer not venting, stopped up drain line etc. If you have a humidifier on your system, sounds like you should, maybe it is stuck on.
    If all else fails....Try reading the directions!

    Tell it like it is and let the chips fall where they may.

    Any views or opinions stated here are strictly my own.


  6. #6
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,642
    Adults add .25 lbs./person of moisture per hour. One lb. of water raises the %RH in 1,000 sqft, of space 8%RH. Your outside dewpoint is 27^F. At 75^F inside, 27^F dp = 25%RH. Add a little inside moisture and you will have 35%RH. Appears normal to me. Let me make this clear. A dehumidifier will not help. Now that was not so hard to say. TB

  7. #7
    Join Date
    Feb 2004
    Posts
    451
    Do you have your fan on continuously. If so the the moisture from the coil could be blowing back into the house in the off cycle.
    Before you criticize someone, walk a mile in their shoes...that way you are a mile from them and have their shoes

  8. #8
    Join Date
    Feb 2004
    Posts
    451
    Just at a home the other day similar scenario.
    Didn't know what was adding humidity.

    A 50 gallon fish tank was the culprit.
    Before you criticize someone, walk a mile in their shoes...that way you are a mile from them and have their shoes

  9. #9
    Join Date
    Jun 2006
    Posts
    4
    Thanks for the replies! We don't run the fan continuously and haven’t recently added any obvious sources of moisture. Another mystery of desert perhaps...

  10. #10
    Did you change the usage duration of the AC unit?

    Do you have a humidifier?

  11. #11
    Join Date
    Mar 2005
    Posts
    997
    35% RH I would not worry about that!!!

  12. #12
    Join Date
    Oct 2002
    Location
    Mahopac NY
    Posts
    448
    Originally posted by drk
    35% RH I would not worry about that!!!
    Ditto.
    Dogs truly are man's best friend!!

  13. #13
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,789
    When did you have it serviced last.

    If the indoor coil is getting dirty, then it may not be removing as moisture as it use to.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

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