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Anyone familiar with a Ventilation device called EZ-Breathe

Post in 'DIY and General non-hearth advice' started by Seasoned Oak, Mar 17, 2012.

  1. btuser

    btuser Minister of Fire

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    Operator Randal just hung up on me. Apparently these units have not been tested for their efficacy against radioactive sea monkeys.


    I'm going to Hell.

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  2. daveswoodhauler

    daveswoodhauler Minister of Fire

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    Well, got it wired up and running....and appears to be working well. I was a bit skeptical about bringing in damp air from the outside, but right now according to the humidity sensor I have hanging directly below the unit, its reading 47% whereas the reading outside is closer to 85%.

    Once the summer gets here with hotter temps and typical humidity, I'll post back.
  3. TradEddie

    TradEddie Minister of Fire

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    What are the temperatures inside and outside?

    I'm at a complete loss to understand how a system without a compressor can dehumidify a room if the temperature and humidity outside are higher. Can anyone explain?

    TE
  4. woodgeek

    woodgeek Minister of Fire

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    If the air get's pulled from the air-conditioned house above, it will help (but work the AC above a little harder).

    If the air get's pulled directly from the outside (or, e.g. from an attached garage) it will make things worse.

    The folks with air conditioned house and problem basements usually have the second case and not the former. So all this is a big waste of time.

    In a house with an airsealed basement and attic, Central AC is cheap to run (outside AZ and FL), and if the basement is damp, just provide some AC supply, or put a return down there, and it will require less energy than a dehumidifer. :rolleyes:
  5. TradEddie

    TradEddie Minister of Fire

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    My basement humidity issues were eliminated when i took a serious effort at air sealing: Bilco door, the rim joist and sill. A lot of effort, but very little cost. Insulating the walls helped a little too. My unfinished area now runs at about 70%@66F in the worst of Summer, and although that's high, its stable, and there are no surfaces anywhere near the corresponding dewpoint (about 55F).

    The only way bringing "fresh" warm humid air into a cold basement will help eliminate mold is by diluting out the smell, possibly even taking some mold spores away. The actual problem of condensed moisture is made worse.

    TE
  6. Seasoned Oak

    Seasoned Oak Minister of Fire

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    If you run these air moving devices at night when the outside humidity is 75-89% you will just bring in more moisture than you are expelling. I have a basement ventilator in a commercial Building ,but i have it on a timer to just run during the day when the outside air is closer to 50% Humidity.
  7. woodgeek

    woodgeek Minister of Fire

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    It's not that simple. The dewpoint is often higher during the day than at night, indicating that the air contains more humidity. The temperature dependence of RH obscures this fact, and is the source of much confusion.
    Last edited: Aug 29, 2014
    Floydian likes this.
  8. TradEddie

    TradEddie Minister of Fire

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    Exactly, that's why dewpoint is a much better way to visualize the problem. Find the temperature of the coldest surface in your basement, if the outside dewpoint is below, or anywhere close to that, don't intentionally draw in outside air. One problem with these conversations, is that we're often from very different climates, giving advice that works well in one, to someone living in another. The same goes for these devices.

    TE
  9. Seasoned Oak

    Seasoned Oak Minister of Fire

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    The weather channel gives the same dew point for the entire day,53 for a range of RH from 50-60 daytime to 80-90s at night. I still tend to think its hard to benefit from drawing in 90% humidity air overnight. During the day temps are in the 80s and at night its about 60deg.
  10. Floydian

    Floydian Feeling the Heat

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    Hi Randy,

    take a look at the psychrometric chart and you'll see the difference between 85::F with 60%RH and 60::F with 90% RH.

    psychrochart.jpg
    Last edited by a moderator: Sep 2, 2014
  11. woodgeek

    woodgeek Minister of Fire

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  12. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I have used the heck out of that thing for a long time.
  13. woodgeek

    woodgeek Minister of Fire

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    I would kill for an indoor outdoor wireless thermo that reported dewpoints rather than RH.
  14. Seasoned Oak

    Seasoned Oak Minister of Fire

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    Great calculator ,super easy to figure. It shows im on the right track for my area by ventilating during the day
    Bringing in nightime humid air would cause a mold risk and twice the metal corrosion vs no mold and half the metal corrosion for daytime air. Daytime ventilation does bring the humidity levels down as long as its not raining of just after a rain.
    woodgeek likes this.
  15. TradEddie

    TradEddie Minister of Fire

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    You are right that there's no benefit to bringing in 60F/90% air at night, but it's the exact same as bringing in 80F/45% air in daytime, so one can't be bad and the other good, they are likely both a bad idea.

    For a stable weather pattern, the dewppint should not change, it's the same air heating up and cooling down. Only when a front comes by or when nighttime temperature cause dew, resulting in lower dewpoint the next day, does dewpoint change significantly. I'm still not sure how you figure its a good idea to ventilate during the day, unless you're a long way from this part of PA, or have no A/C in the rest of the house either. Right now its 88F/52%, that's a DP of 68F. If any part of your basement is below 68F, you're going to get condensation, never mind mold.

    TE
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  16. TradEddie

    TradEddie Minister of Fire

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    I'm going to slightly modify my previous cynical position. Bringing warm air into a cool basement might help reduce the %RH, if it was enough heat to raise the temperature of the basement. It's not taking any moisture out, but raising the temperature so that the %RH falls. That would only work in very limited weather conditions and require a serious amount of air transfer. The numbers in that dpcalc website appear accurate, but it's mold/corrosion figures are for long term preservation of irreplaceable museum artifacts, are are consequently extremely conservative, and also not relevant to human health issues. If its valuable, don't put it in your basement anyway.

    TE
  17. Seasoned Oak

    Seasoned Oak Minister of Fire

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    According to the scale at dpcalc.org there is a big difference.

    80.6° F45% Dp57°F21 Mold risk =none Metal Corrosion 8.3%
    60.8°F90% Dp 58°F254 Mold risk 4 days Metal corrosion 20.7%

    80 Deg air at Rh45 is much drier than 60 Deg at 90Rh according to the chart
  18. Seasoned Oak

    Seasoned Oak Minister of Fire

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    This Bsmt (its in a commercial bldg) is about 85% humidity at 68 DegF After just 1 day of venting it came down 5% . Im also trying to address areas where water gets in after a rain as time permits. This would go a long way to bringing the average Rh down and keeping it down.
  19. TradEddie

    TradEddie Minister of Fire

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    No, they both contain almost the exact same quantity of water, that's why using DP is so much better for this purpose.
    If you could get the basement as warm as the outside air by venting, you'd be correct, but as soon as that outside air cools in the basement, its relative humidity goes up. "Luckily" your basement is so humid that on most days, the outside air will have a lower dewpoint than the basement, and so you are correct that ventilation will be better, but you need to stop thinking in RH and look at the DP when you decide to ventilate. The other side of this is that your basement humidity cannot therefore be due to warm summer air, it is caused by ground/rain water. Anything you do to improve water seepage will give permanent returns. Exterior grading close to walls, and ensuring unclogged gutters can go a long way.

    TE

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