[energy_rater_La]

x2.
mine is tied directly to the supply plenum (70h also).

can be run alone with DH3000 (300?) controller.

If I keep air sealing my house I'll need fresh air provision
& have thought about a barometric damper to control
amount of air entering the house.

size of fresh air duct & setting of damper will
depend upon how much air is required.

fresh air intake ties into return.

dehumidify the air before it enters the house.
hot humid climate here.

what is your location?

best of luck.