RH in basement & crawl space

[Donald]

I have a normal basement and have a dehumidifier for the warm months. I have a condensate pump and pump the water outside onto some shrubs. Next to it is a 3' high crawl space about 10x20. It has a thrown down plastic vapor barrier that is just spread out, not taped to the walls or any high tech method to insure the integrity of the vapor barrier.


I am considering installing a 6" duct with fan to blow from the ceiling of the basement into crawl space. And a short 6" hole through the wall for air return.

The goal is to have the one dehumidifier do both areas?

 

[AZjeff]

How is your d-h sizing? Will it be able to keep up with the additional square footage?

 

[compratio10_5]

Your proposal sounds reasonable if both basement and crawl space are sealed up so that you are not forcing dehumidified air out of the crawl space and drawing outside air into your basement. If you make the air transfer opening between basement and crawl space larger, like two or three times the duct area, the pressure between the two spaces will be closer to being equal and reduce the leakage rate of dehumidified air.

 

[Donald]

Originally Posted by AZjeff
How is your d-h sizing? Will it be able to keep up with the additional square footage?


I would add more dehumidification in basement if needed. There are no easy to get to power outlets or way to drain the condensate in the crawl space like there is in basement.

 

[Fitter30]

Is the crawl space always dry and sealed from the outside? Is there plastic sheeting on the floor? If not you will pull RH from the ground. High RH goes to lower RH.

 

[Donald]

Originally Posted by Fitter30
Is the crawl space always dry and sealed from the outside? Is there plastic sheeting on the floor? If not you will pull RH from the ground. High RH goes to lower RH.


Its a block wall, insulated floor above. Never have seen any water in it. Plastic sheeting on the dirt floor, but that was just laid down, not properly sealed.