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  1. #1

    Can't keep garage Cool and Dry... whats the issue?

    Hey guys,
    I have an attached garage that is also a workshop as well as where my dogs spend most of the day (6 dogs, too many to be all in the house). I want to keep the RH below 50% and keep the temperature below 73f. I live in Raleigh NC.

    The garage is 500sqft, 8ft ceilings.

    I have an idylis 12000 BTU portable AC unit that has window exhaust.

    It is perfectly capable of getting the garage down in the 60's (more than I need), but the RH will always been at LEAST 65% when its running.

    So I got a 70 pint dehumidifier for the garage. I was thinking they'd work well together, but it seems like I HAVE to keep both of these running all day, and the coldest I can get my garage is 77f. If I turn off the dehumidifier the temperature plummest down to whatever the AC unit is set to, but then the RH goes back up to 70 in a very short amount of time.


    Why am I having so much trouble with this? Why is my air getting moist again the INSTANT the dehumidifier goes off?

    My AC unit is vent only, could that be forcing it to suck in humid outdoor air as make up, and if so how do I solve that??


    Thanks!!
    Ryan

  2. #2
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,395
    When the portable discharges the warm air outside it has to be replaced. It is being replaced by hot humid outside air. You are jazz wasting energy. You would get better results with a typical window unit.
    Climate Control Solutions for your Home or Office

    Serving Northeast Philadelphia and Surrounding Areas

  3. #3
    Join Date
    Dec 2008
    Location
    Ontario Canada
    Posts
    548
    Quote Originally Posted by comfortdoc View Post
    When the portable discharges the warm air outside it has to be replaced. It is being replaced by hot humid outside air. You are jazz wasting energy. You would get better results with a typical window unit.
    +1

    Try the dehumidifier with a window unit, likely get much better results. I hate those little portable machines, mostly useless.

  4. #4
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,358
    When people tell me they're thinking about buying one of those portable jobs with just one exhaust hose, I tell them to forget that and get the model with two hoses. They look at me like I'm crazy....I guess because all they see are the single hose models for sale. These should just go away; they're a waste unless it is just for spot cooling.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

  5. #5
    Join Date
    Sep 2010
    Location
    Western, MO
    Posts
    871
    If you could build an exhaust for the dehumidifier you might get there. But you would be doubling your air that has to be replaced. You also might just freeze the evap coil on the dehumidifier. Maybe only run the dehumidifier when it's cool?

    I'll agree that a standard 12,000 BTU window unit should do a better job for you.

    A dry 77° will feel a lot better then a humid 73°. If that's what you can get, that's what you can get.

    jim
    Common sense isn't very common anymore.

  6. #6
    Thanks guys. Of course having it explained like this so simple, I have nobody to blame for myself for this situation, I mean I already pretty much knew the single hose units were crap but I was in a rush buying and as you said, it's all Lowes had in stock...

    I did a test keeping the door to the house cracked while the AC was on and I was shocked how much breeze I could feel being sucked through. But I know that isn't the answer either since then I'd just cause my house to bring in the same amount of humidity... Looks like I need to get a proper unit.

  7. #7
    Join Date
    Aug 2012
    Location
    North Dakota
    Posts
    518
    one pipe portable a\c are a real waste due to this issue the air displacement is huge(its gotta come from somewhere) they should be discontinued and two pipes should be manditory (inake and exhaust)

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