Just bought a house with a dehumidifier in the crawl space. What good is this? Seems to be a losing battle trying to get the humidity out of the air OUTDOORS!! Help! Should I keep this going?

Do a google on Conditioned Crawlspace and Sealed Crawlspace.

You did not give the climate or details on construction.

But in most areas the crawlspace should be sealed off from the outside.

Sorry, I did not give enough information. I'm new to this. The house is in Waynesville, NC, so the climate is four seasons, with mild winters. The dehumidifier sits on top of plastic and was installed to prevent moisture from ruining floors above. Since then, rain water has been diverted via an underground French drain. The dehumidifier runs 24/7 all year. My point is, how can a dehumidifier remove moisture from the air in an open crawl space? It would seem to be a losing battle. We will be installing lattice to cover the crawl space, however, that's for looks only....

What is sounds like what you have is a house on piers, not a crawlspace.

My open crawlspace I though that you ment a walled crawlspace with open vents.

You are right the dehumdifier is not doing any good.

With a house on piers you really need a vapor retarder that seals off the bottom of the house.

Specially if you have AC ducts under the floor.

In general in NC you have very high dewpoints during the summer (may not be as bad in the mountains) and if that moist air gets in the realative cool sub-floor area you will have high relative humidty in their.

I need to learn how to describe the issue better. We do have what is called a crawl space, at least in NC.
On the side of the house and back there are vents. On the front the house sits higher on the land so there are pillars - in some areas 8' high. The entire area is considered the crawl space - the section that has vents and the section that has wood pillars supporting the deck above it. That's where the dehumifier is...in the middle of this area with vents and pillars. There is plastic on the ground to prevent moisture from getting into the floor above. However, there is no plastic on the underneath portion of the floors in the crawl space. Does this explain it better?

If the area is that open the dehumdifier is not doing any good.

I am not sure, but I think that this article describes a similar house, but that piered area has been closed in.

http://www.jlconline.com/cgi-bin/jlconline.storefront/4712210e000caf8727177f0000010561/Product/View/0408fixi