Crawlspace vents..open or closed

Last month Kentucky had over 8 inch’s of rain. This in turn made for a lot of wet or damp crawlspaces.
Recently I spoke with two different HVAC repairman about excessive condensation dripping off ducts.
They both told me that they instruct home owner to keep the crawlspace vents closed. Years ago they said to keep them open. Why have they changed their stance on this?

They’re right! Google it.

http://www.bestofbuildingscience.com/pdf/Closed%20crawlspaces%20do%20double%20duty%20HEM_SP05_p32-36.pdf

Heat hitting the cool ducts with the high ground humidity… =sweat…
Closing the vents allows the ten to cool and the differential is less reducing the condensation.
BUT if the crawl is visibly wet/standing water they have other issues as the amount of rain still should not cause standing water

That was a great article to read and make good sense.
Thank you

Every home is different. That’s the result of my study over 18 years. Some you can leave open year round with no issues, some closed with no issues.

Is it written out Brad?

more info here.

http://www.justcalllarry.com/pdf/HomeEnergyDryingoutacrawlpace.pdf