Built our home five years ago and our crawlspace is 2300 sq ft. For awhile ran a residential dehumidifier till it went out. I do understand that placing this in the crawlspace wasnt the best ideal solution but at the time it worked.

So far it's almost been a year since I've looked into adding another one but due to being in a high humid environment and noticing my family's allergies are worse this year I thought it would be time to do it right. I recently received quotes and had tests performed for encapsulating.

At this moment I'm at an 85% humidity in my crawlspace. Based on my sq ft I've decided to go with an Aprilaire 1850 center in the crawlspace and when the home was built it we installed a dedicated 110 outlet on a breaker and drain line already goes through the concrete blocks but I'm going to install a pump to assist since the dehumidifier will be a distance away, around 20'.

My entire main floor is 90% hardwood and the other 10% is tile. From my research I've seen where some refer to adding the Aprilaire into the air supply ducts. So this leads me to ask should I be adding the dehumidifier to the crawlspace and close the crawlspace vents (twelve total) and installing one exhaust vent or installing the dehumidifier into the central HVAC system? Is it possible I need both?

Research I've done and other questions I've read:

If it helps yes at season changes we've heard the hardwood pop but no issues as of this moment and we have had door closing issues from the humidity on one closet door. Mining humidity in the bathrooms they can range from average 50% to a hot shower shooting it up to almost 70%. Location is in the south so we see single digit winters and over 100 in the summers.

  • I didn't read the linked articles but thinking wouldn't it be more effective to protect the underside of the floor with the vapor barrier, if possible?
    – r13
    Commented Jul 12, 2021 at 1:35
  • There is a vapor barrier and also rock that was laid down when built. Commented Jul 12, 2021 at 2:04
  • Is the vapor barrier on the ground or directly attached to the underside of your floor? If it is the latter, you only need to find a way to provide better ventilation to the crawlspace.
    – r13
    Commented Jul 12, 2021 at 2:23
  • Vapor barrier is on the ground and underneath are rocks Commented Jul 12, 2021 at 2:30
  • That cuts down the moisture from the ground (due to high water content) to the crawlspace, but it is not effective in preventing the moist air and vapor (brought by the wether) from getting into your house through the floor. Unless the crawlspace is not high enough to allow a person to work underneath, I suggest installing the vapor barrier as an alternative to the humidifier, as the former is a (one shut) permanent solution, if installed correctly.
    – r13
    Commented Jul 12, 2021 at 2:50


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