u/Farmboy1539

Hey everyone,

I’m looking for some advice and a quick sanity check on a dehumidifier plan I’ve put together for my basement. It’s got a pretty unusual layout and a high moisture load, on the east end. My drawing is not to scale.

The Setup & Specs:

• Size: ~1,400 sq ft total footprint, unconditioned (no central AC, hot water radiators/boiler for heat, window ACs upstairs).
• Foundation: 9" thick brick with a parge coat on 95% of it and 3 1/2" concrete floor. The house is graded out nicely and there is no flooding or standing water, just some damp wet spots on walls and floor in various places
• Current Climate: Hovering between 70% and 75% relative humidity right now.
• The Layout: It's split into 5 rooms with, doorless openings.
• The Catch: Room 4 and Room 5 are the absolute wettest zones, and they are completely separated from each other by a wood wall that was also an old pantry in room 5. There is an old brick and concrete porch east of these rooms that has settled over time and now the rainwater runs off towards the foundation causing the issue. (plan to demo and rebuild in distant future)

Current Plan:
Instead of trying to run one 100-pint commercial unit (HDi 100) centrally located in room 2 or 3, I'm thinking of buying two smaller commercial units. Specifically, the AlorAir Galaxy 60P (60 PPD at AHAM / 165 CFM each, 120 PPD total).

The Proposed Placement:

• Unit 1: Placed directly inside the threshold between Room 3 and Room 4. Intake facing into the wet Room 4, exhaust shooting dry air north/west into Room 3.
• Unit 2: Placed directly inside the threshold between Room 2 and Room 5. Intake facing into the wet Room 5, exhaust shooting dry air west into Room 2 (pointing toward the Room 1 opening).
• Airflow Logic: By bridging the doorways, the intakes draw raw wet air from the dead ends, and the exhausts push dry air into the central rooms. The dry air should migrate into the large Room 1 naturally, while the brick cutouts around the radiator pipes acts as a free return channel back to the intakes.

My Questions for the Experts:

1. Will this threshold placement and sizing prevent short-cycling?
2. With Room 4 and Room 5 split by the wood wall, do I need to worry about the two units "competing" for air, or do the radiator pipe openings provide a safe pressure relief? (again, short cycling worry)
3. Is 120 PPD (AHAM) total capacity enough punch to push past continuous moisture coming through 9" of uninsulated brick walls?
4. Would one centrally located 100 PPD unit instead be enough to handle the multiple rooms?

Any additional thoughts, feedback on the layout logic, sizing, or machine choices would be highly appreciated before I pull the trigger and buy the equipment. Thanks!