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I Basement humidity

  1. Jun 1, 2017 #1
    not exactly sure where to post this, or if this is the right place but,

    my problem is controling humidity in my basement,
    what id like to do is be able to let in the cool nights air without making the basment humid

    what im doing now is running a large vollume dehumidifyer unit (90pt/perday) on contineous in the open area, and a "large room" space heater in my room just to maintain ~40% in my room
    (room is 12x12 with incompleat walls "curtained off" by a tarp or quilt but dosent "feel" drafty)
    but that means its 75-80f in my room, which compleatly oblitherates the point of having a room in a basement
    (the cool temps)

    for those who arnt aware, once you hit 40% in a basement, your bedding starts to feel damp
    and thats just gross

    i guess my questions would be, in laymans terms what is the phenomenon that causes basements
    to be humid despite dryer air conditions outside or in rest of house

    and is there a way to prevent that phenomenon, or remove said humidity without
    requiering warming the air
    (running an AC unit or installing "central air" is not an option

    ps, sorry about rambling like a confused idiot
    also sory if it double posts, my pc laged and i dint see it come up or a mesage after clicking create
  2. jcsd
  3. Jun 1, 2017 #2


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    That is amazing. The average humidity in the UK is in the 70s and 80s percent and, yes, it can feel humid but not "gross" bedding.
    Have you thought about getting hold of a moisture meter? Cheap enough and easy to use over the walls and floor.
    If the bedding feels humid, the meter could actually test it.
    As for a possible mechanism, how about warm walls and cold bedding? Could it be perspiration?
    What's the outdoor temperature / humidity?
    Are you sure about your humidity measurement? Try another meter and another location.
  4. Jun 1, 2017 #3
    not realy sure how to respond
    for my measuments, im going by my room thermometer one of these https://www.walmart.com/ip/AcuRite-...8060075&wl12=16888914_0&wl14=accurite&veh=sem
    ...sorry bout huge url
    (dont really want to spent ~50$ on a meter just to use it once)

    for annecdotal referance, last night it was ~68f and 31% in first floor with windows open so i think accurate to outside minus wind factors
    meanwhile the high/low on my thermometer says after i turned my heater and dehumidifyer off and went to sleep
    it went from 74f 39% to 68f and 48%,
    but if i had opened windows in the basement humidity woulda been nearing 60% (ill test that theory tonight for accuracy)

    now i understand that "feels" humid is also relative to some factor im not aware of, ie during sumer when i manage to get ~ 75f ~35% in room
    it feels the similar as winter when i get 75f 20%, the season makes a differance, ie 35% is great in summer, but in winter 35% makes bedding feel damp

    im moving the thermometer out from my room and into the main space of the basement, as to get a reading without my heater as a factor
  5. Jun 1, 2017 #4


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    I think it could be worth while making sure that your Humidity Meter will give a 100% in saturated air (calibrate it at one known point). That isn't hard to provide in a large plastic bag with a wet towel in. It's not so much that I doubt that your bedding feels damp. It's that I am not too happy that you feel that at such low humidity. Eliminate the impossible and you are left with the possible (Sherlock Holmes - not so much a Scientist, more a smartarse. But he had a point) 30% is recommended as minimum to avoid low humidity distress (Rhinovirus probs))
    Buying a moisture meter wouldn't need to cost $50 if you get a cheap one from eBay. They are available for less than ten bucks. Not highly accurate or sturdy but useful for the rest of your life. I got one for firewood and have used it twice for other applications already.
    The problem with this situation is that you need to measure things accurately and compare them with established knowledge. You perhaps need a DIY or housebuilding forum to get not-so-scientific stories. So many people live in damp basements that there is bound to be a wealth of experience.
  6. Jun 1, 2017 #5
    im not quite happy either, lol
    ya i dont know what it is, but as much as maybe i just dint notice as a child, since my late teens
    ive been kinda sensitive to humidity, once its >55%, i start "feeling like im drowning" the air gets thick, and i ocassionaly will choke

    so i try to keep my "personal environment" dry (meaning my room, since its the only place i got full control of)

    when comparing our situations, im sure it is a matter of not being used to it, like you would be with your 70-80%
    when it gets that way for me, i cant even go up to the first floor and sit in the living room cause its just so wet feeling
    (it actually feels dryer being in the shower (lukewarm not steamy))
    nearly makes it impossible to eat, with the difficulty of breathing

    i kinda agree that i probably need to inquire on a housebuilding forums, cause the looking ive done on the general web over the years, basicaly dosnt say more than use dehumidifyer, central air, or have a compleated basement (usually meaning central air or seperate environmental contols)

    but ill leave those poor unsuspecting folks alone for now, as i have it managed... kinda, just wish i could let in the cool fresh air once in awhile, gets kinda stale being a closed up basement and all

    thanx much
  7. Jun 1, 2017 #6


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    Or see a medical doctor. Many dollars, but potential for long term/permanent relief. Reminds me of asthma or an allergy. I'm way underqualified here, but I know a few people with asthma and I've developed some minor allergies over the years and it seems plausible.
  8. Jun 2, 2017 #7


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    Have you checked that your meter is calibrated? As I wrote, earlier, you can give yourself a good 100% humidity as a calibration point.
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