Fan Operation: Ducted vs. Non-ducted a/c

The ambient roomtemperature swings are greater in a non-ducted system. That's why the fan runs all the time.

Our 5th wheel has only one 15k unit, which is ducted but you can open the vent in the main room so it all dumps in the living area. I always leave the fan on full time to keep the air circulating. We close the dump vent in the evening and the air circulates nicely at night. Again with the fan on all the time. I prefer the grey noise when sleeping. I would think you would be able to leave the fan on all the time on both AC's

Ours works that way also, but we do have a setting on the thermostat to indicate "auto" which will make it turn on/off with the AC, or on, which will keep it running constantly. We keep our on auto for both our front and read AC - they are both ducted.