Supply Air Adjustable Drying Mechanism for Sealed Crawlspaces

By adam
January 28, 2021   Comments Off on Supply Air Adjustable Drying Mechanism for Sealed Crawlspaces
Adjusted way down. 2 flaps are screwed shut. We provide the option to add a 3rd screw for complete closure.
Ideally we can put the device on an exiting box. This is standard 🙂 really just opened that second flap to make this flag dance a little more 🙂

Stetten Home Services does such a great job getting everything in the crawlspace airtight, the above amount of air is overkill. We eventually turned it off. The crawlspace crawlspace shown above remains dry without intentional drying. Time and time again, we prove to ourselves and our clients that you do not need a dehumidifier. In fact, you don’t even need ductwork in the crawlspace to use your home’s dry air to keep your sealed crawlspace dry year-round. Even if you have unfavorable moisture impacts, the code provides other ways, see 409.5 , that are effective in tought situations.

DUCTED DRYING MECHANISMS – Adverse Conditions…

What happens if the air-handler is in the garage and the ducts are in the attic? Wilmington:

Run a duct from the garage adjustable sealed crawlspace drying mechanism.
This is a great option to explore before trying to run an electrical line, drain-line, etc for a dehum.
During our walk-through we told this builder to run a 6″ duct through the master closet. It was “His Closet” as it turns out, and we put an access to a damper in there at eye level. He was nerdy and had felt the pain of a wet one. This amount of air was drastic over-kill for 2700SF. We were learning!

HOUSE-AIR Adjustable Drying Mechanisms:

NO DUCTS AVAILABLE? “STEAL from the HOUSE”

With no access to any ductwork, we can install a small 4 inch fan, a new register, under the doorway to the coat closet for example, and pull a little air out of the house.

The owner installed an outlet in the corner to the right for the new fan controller.

The house is verified to be about 50% rh through the wet seasons… so we take 25-50 cfm and that is often overkill.
we like to hang the indoor basestation near the thermostat, since the adjustment is generally running the A/C a little cooler or running the fan. This was right after we did the crawlspace and this home had their windows and doors open, we consider 67% indoor humidity excessive. We shoot for 50% or 55% from May through October.
The humble humidity sensor allows us to always know what works, and what doesn’t.

We really only need to keep crawlspaces below 68% to 72% RH depending on hot or cool the air is inside. Regardless of the situation, we find that the humid periods are spring/fall when people are comfortable without AC / HEAT. Then when it rains everything gets humid. after 5-10 days all those blips are over. A little risk is okay because overdoing it is energy waste and can lower IAQ.