Do Crawl Space Fans Control Humidity?

Could adding fans to control crawl space humidity be doing more harm than good? Michael Church of Crawl Space Ninja joins us to dispel a common misconception in the crawl space repair and pest control industries. He explains why relying on ventilation fans might not be the best tactic, especially in humid climates like the South. Michael shares his expertise on how these fans can inadvertently draw in more humid air, ultimately making the problem worse. His insights are backed by years of experience and research, providing a fresh perspective that challenges conventional wisdom.

Tune in as Michael highlights the importance of using a properly sized crawl space dehumidifier instead of depending on your HVAC system or ventilation fans. While fans can be effective for venting soil gases, they fall short in managing moisture levels. He emphasizes methods that will help you achieve a healthier, drier crawl space environment. This episode is a must-listen for anyone looking to improve their crawl space repair strategies and ensure long-term effectiveness.

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Episode Transcript

Speaker 0 (00:00):
Hey, michael Church, crawl Space Ninja.
We are continuing ourmisconception series and today I
want to talk to you about manyof the professionals out there
in the pest control industry andin other crawl space repair
talking about using fans tocontrol humidity.
Is that a good idea?
When I got started in crawlspace encapsulation, it seemed

(00:22):
like everybody was doing thesame thing.
They were putting down a looselay vapor barrier and installing
crawl space ventilation fans tocontrol humidity.
And I got to thinking you know,we live in the South where it's
really humid outside.
So if I put a fan in the crawlspace vent and some people would
install them in the door if Iput a fan and I'm pulling in wet

(00:44):
, humid air into an already wetcrawl space, how is that really
controlling humidity and dryingout the crawl space?
I've even done some moisturereadings where the fan itself
was blowing in 80% relativehumidity inside the crawl space.
And then you got those onesthat argue about well, you blow
the fan out to control humidity.

(01:07):
Well, it's still pulling makeupair from the outside into the
crawl space.
If all of the other vents areopen, that makeup air has to
come from the outside into thecrawl space.
So whether you point the fanblowing out or you point the fan
blowing in, the makeup air iswhat is determining the humidity
level of the crawl space.

(01:27):
So what we have found over theyears?
Research has shown over andover and over again that you
need a dehumidifier.
Don't use your HVAC system forreasons that I've mentioned
before, and if you check out themisconception series, you can
learn about that.
Install a crawl spacedehumidifier that is properly
sized and also have theventilation fan to blow out

(01:50):
those soil gases but not tocontrol humidity.
So we feel like that'ssomething a lot of companies
should stop doing is using fansto control humidity.
You can use it to control soilgases.
Michael Church, crawl SpaceNinja.
We hope you make it a happy andblessed day and we'll see you
later.