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  1. #1
    Join Date
    Jul 2006
    Location
    Columbia, SC
    Posts
    96

    Dehumidifier options

    I want to put a dehumidifier in my crawlspace. Ground has been covered w/ 6mil plastic. Vents have been covered and sealed. As much as I would like to, Aprilaire and SanteFe are not options, way more than I can spend. Is there a decent unit I can use that won't break the bank? Crawl is a little under 1300 sq ft. What capacity should I look for?

  2. #2
    Join Date
    Sep 2004
    Location
    Georgia
    Posts
    103
    A dehumidifier has a dx coil and the condenser coil in the same unit. If you are clever with controls, isntall a 12,000 btuh window shaker in the space making sure that the condenser section rejecting the heat in the space too. Disconnect the thermostat and replace with a de-humidistat. Vinal tube the condensate away from the space. AC units aren't optimized for dehumidification, but you will pull more moisture out of the space this way than if you did nothing.

    Disclaimer: I've never tried this.... it's one of those "It outta work to some degree" things.

  3. #3
    Join Date
    Oct 2005
    Location
    Buffalo
    Posts
    195
    Look at the energy consumption of the proposed 'window shaker' application and that of an E-Star rated unit designed for dehumidification. I agree that the Aprilaire (and others) are a bit of a price to swallow...but they are designed for the application and will pay for themselves with better performance and lower energy usage. Sometimes you get whatcha pay for!
    Eager to learn, willing to teach, reluctant to admit defeat.

  4. #4
    Join Date
    Oct 2002
    Location
    Florida Panhandle
    Posts
    4,371
    Quote Originally Posted by dryguy View Post
    A dehumidifier has a dx coil and the condenser coil in the same unit. If you are clever with controls, isntall a 12,000 btuh window shaker in the space making sure that the condenser section rejecting the heat in the space too. Disconnect the thermostat and replace with a de-humidistat. Vinal tube the condensate away from the space. AC units aren't optimized for dehumidification, but you will pull more moisture out of the space this way than if you did nothing.

    Disclaimer: I've never tried this.... it's one of those "It outta work to some degree" things.
    Window units are designes to take the condensate to the rear condenser fan, which has a water slinger on it to use the water to help cool the condenser. Unless you remove such a water slinger you would re introduce the humidity right back in to the space, not to mention one would have to drain water away form unit.

    Roy
    "The perfect Totalitarian State is one where the political bosses, and their army of managers, control a population of slaves, who do not have to be coerced, because they love their servitude"

  5. #5
    Join Date
    Jul 2006
    Location
    Columbia, SC
    Posts
    96
    OK I broke down and bought a Comfort Aire 50 pint unit. I have done a little research first and Comfort aire brand is supposed to be one of the better cheap portables. A little small for 1500 sq ft I know but should work for what I need. I have used it in the house to test first. Usually humidity runs between 40% to 50%. I measure this with a small pocket weather station I got from Lowes. Measured in the largest open area which is the kitchen/dining room and living room, a little over 400 sq ft. Ran the dehu in the same space for a week. Humidity never went over 43% and went as low as 37%. I put it in the crawl space today and will test. When I put it in about 10 am it registered 65%. Last check at 7 pm it was down to 45%. What would be a good humidity level to shoot for in the crawl space?

  6. #6
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,360
    50%RH is excellent for a crawlspace. Rainy, windy, and cool weather is the highest load condition to check your ability to control humidity. A poor dehumidifier is better than "no dehumidifier". Your dehu is 2X higher operating cost and may be less durable than the better units like Santa Fe. Consider getting a good unit next time. Dehu TB

  7. #7
    Join Date
    Jul 2006
    Location
    Columbia, SC
    Posts
    96
    Thanks TB. This was basically a Ebay unit I got cheap to test with. When I have to replace my gaspack unit I will get a good dehu unit to go in the system. Not a good test day really, 35% and 91 degrees outside. But it has maintained a 50% level but I have to dump the 22 pint bucket daily. Need to run a hose to drain or get a pump. Will the crawl ever "dry out" enough to be able to remove it or just run it every so often? It's closed off fairly well but not airtight.

  8. #8
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,360
    Quote Originally Posted by jl1 View Post
    Thanks TB. This was basically a Ebay unit I got cheap to test with. When I have to replace my gaspack unit I will get a good dehu unit to go in the system. Not a good test day really, 35% and 91 degrees outside. But it has maintained a 50% level but I have to dump the 22 pint bucket daily. Need to run a hose to drain or get a pump. Will the crawl ever "dry out" enough to be able to remove it or just run it every so often? It's closed off fairly well but not airtight.
    Operate the dehu on its dehumidistat set at 50%RH. The dehu will shut off when not needed. Expect the dehu to operate whenever the outside dew point is above 50^F. During weather with dew points below 50^F, the dehu could be removed, but why? Dehu TB

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