Hi, I have a conditioned crawl space. Background - It has the following: approx. 10 mil vapor barrier, standing room of 6-7 ft., spray foam insulation on crawlspace walls (of course with no vents to the outside), it is dry and pretty clean. It has one supply vent from the home's 3 1/2 ton Lennox HVAC unit to the approx. 1900 s/f crawl space. The one supply in the crawl space has no return, that I can find, but supplies enough air to keep the space very cool even in my Middle Tennesse 99 degree, humid summer temperature. I believe the RH to be approx 60-65% in the space. I would like to make this space as dry as possible <50% RH as recommended. I would also like to filter the air to utilize this space as extra, "man-cave" living space. Since I might be spending a lot of time down there, the filtered air is important to me. A basement company in my area sells the Sanidry brand Dehum / filter. My question is: Would this be a good solution to dehum and filter the air? Additionally, If I had the Sanidry's exhaust air piped to the outside of the crawlspace would that be o.k. and not mess up the supply from the HVAC unit (or the HVAC unit itself)? I am considering doing this just in case I have any radon or other gases coming up through the vapor barrier that has a few seams separating. The home has a minimal Radon PVC pip under the vapor barrier passively exhausted through the roof of the home, but I'm not sure how effectively that is working. I have not had the home Radon tested, but am concerned about that since the PVC pipe is the only means of allowing this air to escape. Any suggestions would be greatly appreciated!