east room is more humid.

Is there soffit vents and and a ridge vents?
What's the outside humdity?

I suspect the soil below the crawlspace surface you are calling dry is actually moist. The surface looks dry because the moisture evaporates as it comes near the top.

One approach to isolating the source of moisture is to place humidity meters many locations. You would want to measure both humidity and temperature as the RH varies with temp. Then, you need to look at how the air moves through your home. Typically during cooler months the crawlspace air moves up through the house and out leaks near the top. That is why we are pointing to the crawlspace.

I'll add the link for comparing RH at different temperatures. I can review the process if needed.
http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html

Also, note the temp and RH outside each time you take an inside reading
Bud

Is there a vapor barrier on the ground in the crawl space?
If not that building 101 that there be one.

thanks all
outside humidity is 60%
yes there are roof and soffit vents.
vapor barrier? I sure hope so, we don't want to dig up the concrete to find out!

will have to find out what a dew point is!

Please determine why the discrepancy in the humidity readings with more and accurate readings before constructing a termite breeding ground vapor barrier in the crawl.

good idea! thanks