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Oil Heater, Humididy, Heating Cold Air

  1. Dec 2, 2008 #1
    Hi im living in a 2 bedroom house with base bord heaters but i have also purchesed 3 oil space heaters, my landlord since has givin me a bogus eviction notice because of to much humididiy in the air, his fault really for nothin ensuring propor ventalation when repairing the house

    but my question is that if space heaters, brand new ones at that when heating cooler air like in the moring or later at night with air cirulation (ceilling fans) causes dry air, more humididy or just a neutural mix.

    any coments would be greatly appretiated,

    thanks.
     
  2. jcsd
  3. Dec 2, 2008 #2

    mgb_phys

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    If the ventilation is poor enough that you are concernd about the water form gas heaters I would be more worried about carbon monoxide!
     
  4. Dec 2, 2008 #3

    russ_watters

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    There may be a wording misunderstanding there, mgb - I think the OP is talking about oil-filled electric heaters, not fuel burning heaters (which are not, by code, allowed to vent inside).
     
  5. Dec 2, 2008 #4

    russ_watters

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    Bottom line first: too much humidity is extremely difficult to achieve in winter and is most certainly not possible without actually injecting moisture into the air.

    Several important points:
    1. It is a fundamental principle of mixing of gases that all gases in a mixture act independently of each other. That means that the absolute amount of moisture inside and outside the house will try very hard to equalize. Unless a house is extremely airtight and/or has a constant supply of humidification, moisture inside will rapidly force its way out out of the house due to the unequal vapor pressure.

    2. Changing the inside temperature will change the relative humidity, but it will not change the absolute humidity. For most climates, a good rule of thumb is that the absolute humidity is roughly equal to the daily minimum outside temperature. That's because the earth radiates heat at night until the air temperature reaches the dew point. To figure out what this means, have a look at a psychrometric chart: http://www.truetex.com/psychrometric_chart.htm Sensible (regular) air temperature is along the bottom, dew point is on the y axis (shown on the left), and relative humidity in the curves. Notice, if the dew point (absolute humidity) outside is 35 F, you can trace sideways until you get to your inside temperature - say, 70F - and find that the house will tend to seek a relative humidity of 25%. It is pretty difficult to consistently maintain a delta of more than 10% between this and the actual humidity inside. In other words, without active humidification, you won't typically see more than 35% relative humidity if it is 30F outside.

    3. What can you do about this? Get a decent temperature/humidity sensor. Oregon Scientific makes the best consumer ones I've seen and you can get them at lots of retail stores (or onliine) starting at about $15. Record what it says on a daily basis. Also, look for (and demand from your landlord) actual evidence of humidity problems. A claim without evidence is an invalid claim.

    4. Caveat: there are some unusual situations where condensation can occur, and I'd need to know more about what the landlord is claiming to know if they apply. These would include tight construction but with single-pane windows, windows in bathrooms (ie, shower-caused condensation), tight, but poorly insulated walls or floors (that is a real killer for a house, but couldn't be your fault). FYI, basements in a climate with a real winter are never overly humid in the winter.

    If your landlord wants out out and is willing to invent a reason, you may not really want to stay, but then again, if you do, you'll probably need the help of a lawyer. The science here is pretty straightforward, though, and the fact that he's doing this in winter works to your advantage, not his.
     
  6. Dec 3, 2008 #5
    they are infact electric oil filled heaters and the landlord himself upon signing the lease stated that he did everything possible to keep it air tight and sealed up for the winter
    the information you gave me helped explain a great deal but

    "Unless a house is extremely airtight and/or has a constant supply of humidification"

    could those heaters be a contributor as well as the electric basebord ones i chose not to use for the most part or could the humididy be soley from showers and and other minor use of water along with the house being as air tight as a house can be

    also the basement floor isint insulated what so ever and it tends to flood a little in the corners from time to time when the snow melts a little or when it rains ( in ottawa ontario right now its only begining to be winter at the most the tempeture outside is be +5 c
    and - 10 c to maybe -15 c at night) inside its stays about +20 c

    im a smoker (heavy at times) and this is back in the early fall when i could open a window to cool the house i'd have to open the from door and the side door and a window or two too vent the ciggerette smoke out of the house and it took an unusaul amount of time to vent it outside almost 3 to 4 hours even with a cross breeze

    and there isint any damage from ecessive humididy to the rental unit only to me and my girlfreinds skin and i have a laywer just want to know a thing or two myself

    any and all information, questions awnsered would be most greatful i could really use some help with a few bit and peices right now
    thanks again.
     
  7. Dec 3, 2008 #6

    mgb_phys

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    The electric heaters can't add any moisture to the air, sorry that was my confusion with your first post - the LPG burners you use to heat a house on a construction site do add a lot of water.
     
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