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How dry is too dry? Room humidity...

Post in 'DIY and General non-hearth advice' started by Swedishchef, Dec 12, 2013.

  1. Swedishchef

    Swedishchef Minister of Fire

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    Hey guys

    So my stove has been running 24 hours a day for the past 4 days. My basement humidity has reached 30%. I have a humidifier running constantly (albeit at a low rate) and I burn about 1-2 gallons of water a day.

    How dry is too dry?!?!

    Andrew
    Last edited: Dec 12, 2013

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  2. mustash29

    mustash29 Feeling the Heat

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    Very dry is when your hardwood boards shrink and leave gaps, your skin dries out and you find yourself applying moisturizer lotion like it's sunscreen, LOL.

    Too moist and you can start growing mold in places you don't want, and your windows will be sweating a lot.

    When I was running a large stove (rated to heat 2100 sqft but heating 1800) it had a 3 gal SS stock pot sitting on the top. I could cook off anywhere between 3 - 6 gallons per day depending on the firing rate of the stove + another 3 - 4 gal in the humidifier. Now that I am running an Englander 28-3500 it is a lot drier in the house, because I lost that superb flat cook top surface.
    Swedishchef likes this.
  3. Dana B

    Dana B Feeling the Heat

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    Swedishchef likes this.
  4. Swedishchef

    Swedishchef Minister of Fire

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    Great link! Thanks!
  5. maple1

    maple1 Minister of Fire

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    Doesn't matter - if you can burn water you've got it made regardless.

    Watch out for black helicopters though.
    Swedishchef and oldspark like this.
  6. maverick06

    maverick06 Minister of Fire

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    everywhere i have read says about 40-50% RH. I try to keep my place at 45%, its hard to do with the 1 humidifier have, about 2gal/day... I have an ultrasonic humidifier, using tap water it generated the "fog" "white mist" whatnot from the evaporated disolved solids, i have since bought a reverse osmosis filter and that solved all problems with the humidifier!
  7. altmartion

    altmartion Feeling the Heat

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    it is a general rule of thumb. the formula is great, but i don't understand (yet) how it is helpful when adding or removing moisture. humidifiers and humidistats have percentage for settings. does somebody make a stat or porttable that works off the formula? i just have never seen one. i prefer it around 45%
  8. crossout

    crossout Member

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  9. altmartion

    altmartion Feeling the Heat

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    the more i think about it, i think i read about a humidifier with an outdoor sensor. was it a trusteam maybe?
  10. crossout

    crossout Member

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    its a stand alone whole house humidifier
  11. woodgeek

    woodgeek Minister of Fire

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    I think the window is >30% for reduced winter colds and <50% for reduced dust mites. >70% runs into indoor molding issues.

    The problem is that 30% RH air at 70°F starts condensing water when cooled to .... 37°F (dew point)
    (calculator: http://www.dpcalc.org/)

    So, if air is exiting your house into an attic, wall cavity, storm window cavity with a surface below 37°F, that surface will be wet and soaking up water all winter long.

    This is why airsealing and running a small/no humidifier is safer for your house structure than running a giant humidifier in a leaky house in a cold climate. That would worry me. As it is, in an older house I would stick to the lowest value of RH I need for comfort, e.g. 30%.
    Swedishchef likes this.
  12. Swedishchef

    Swedishchef Minister of Fire

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    All I know is that I have not yet had a nose bleed. So it could be worse..30% downstairs right now.

    Andrew
  13. maple1

    maple1 Minister of Fire

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    I just checked the little meter in our living room. 31%, 20.2°c. That's right in the middle of the red 'too dry' zone on the display. Don't think I'll worry about it though.

    -19c outside this morning - brisky days are hitting earlier here this winter.
    Swedishchef likes this.
  14. Swedishchef

    Swedishchef Minister of Fire

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    NS is getting hit too eh? Even Halifax?
  15. maple1

    maple1 Minister of Fire

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    Yessir.

    Big blizzard supposed to hit tomorrow too. Been battening down hatches this morning before I go out for the day. I used to like winter, but not quite as much now, it seems.
  16. Swedishchef

    Swedishchef Minister of Fire

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    HAha. We are not getting as much as forecast (good!) but I am sure we will get another 300-400cm before the winter is over (our average is 300-400!). Keep it south my friend, keep it south!
  17. altmartion

    altmartion Feeling the Heat

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    yes south. but farther south than me. lol at least for a while.
    Swedishchef likes this.
  18. Swedishchef

    Swedishchef Minister of Fire

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    lol
  19. altmartion

    altmartion Feeling the Heat

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    you jinxed me!! I just saw on the news we are supposed to get it today and tonight too!! it started an hour ago but I thought nothing of it till I saw the news. thanks swedishchef, much appreciated. lol
  20. Swedishchef

    Swedishchef Minister of Fire

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    Snow is the gift I can give you that will last for months! You're kindly welcome.
  21. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Meanwhile back at humidity...

    I shot for the 45-50% mark because of some health problems. There is now all new plywood roof decking on this house thanks to the mold that exploded that year. Fortunately, kinda, it was time to replace the roof anyway.

    I now shoot for 30-35%. That and I now have better attic ventilation and closed a huge mistake the builder let happen from the basement to the attic.
  22. Swedishchef

    Swedishchef Minister of Fire

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    RIght now it is 25% in my basement. I feel like my skin is about to shatter like a mirror.
  23. woodgeek

    woodgeek Minister of Fire

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    Sure your instrument is calibrated? Hygrometers are famously inaccurate. I don't fee uncomfortable until <20% or even notice until <30%.
    Swedishchef likes this.
  24. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I have three of the two buck ones from Walmart, picked up the three that all agreed, two wireless ones and the one on the Sunbeam humidifier. They all dead on agree.

    Amazed me.
  25. Swedishchef

    Swedishchef Minister of Fire

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