1

This is a highly debated / discussed topic, but pretty much all of it based on parts of the country with relatively very high humidity.

I live in San Diego, where humidity is moderate most of the year (60 - 80%). Due to grading issues my crawlspace gets wet during rains. I have decided to do a French drain, sump and vapor barrier.

Question is: will a few ventilation fans in the existing vents (and seal the rest) suffice to control humidity in my area? Or should I seal of all the vents and put in a dehumidifier?

I understand it is actually the dew point differential between the outside and inside that matters, but I am unable to gauge what factors could lead to my crawl space having a lower dew point that the relatively low dew point you find in San Diego most of the time.

FYI I don't have an A/C in my house and the heating ducts run through the attic and not the crawl space.

Thank you!

isherwood
  • 158,133
  • 9
  • 190
  • 463
SAS2Python
  • 141
  • 7

2 Answers2

3

Fans are usually much cheaper to buy and run.

I would start with one or more fans and try it out for a decent amount of time (more than a month) and see if you are happy.

You might want one of those desk/floor fans that move to mix up the air at the opposite end of the exhaust vent.

isherwood
  • 158,133
  • 9
  • 190
  • 463
crip659
  • 32,986
  • 2
  • 39
  • 85
0

The general recommendation here in Sweden is to use dehumidifiers, the reason is that the outside air will be cooled in the crawl space. When hot moist air is cooled, a sharp increase in humidity or, in the worst case, even condensation occurs.

Rsf
  • 202
  • 1
  • 5