A year ago we had a Fujitsu mini split installed. One outside unit that drives four indoor units (heads?)- 3 bedrooms upstairs and a larger one that does the downstairs. Couldn't be happier, it's fantastic.
My question is regarding the daily operation. The kids are gone so 2 of the bedrooms are off except when they visit. This question is about the daily operation of the one upstairs unit (our bedroom) and the one downstairs unit (the entire first floor) Our installer (who is fantastic and I trust completely) says it is more efficient to leave them both on all the time even if you were to turn up the temp when you are not using the room as would be the case when you leave the bedroom in the morning or leave the downstairs to go to bed in the evening.
For me, the whole point of separate zones, is to turn them off until you need them. I'm trying to wrap my head around any idea that leaving it on, even set to a higher temp (we are only talking about summer A/C operation here) is somehow more efficient. He also mentioned that moisture builds up in the unit and letting it run helps by drying that moisture out.
I ask because I know many here have mini splits installed and I'm simply looking for the logic involved re letting it run vs only turning it on when you are in that room and need it. Don't forget- we will crank up the temp when we are not in the rooms- specifically, the bedroom during the day, and the downstairs at night.
Thanks for reading, numerous edits were made to try to make this simple yet specific.