I have central air that needed help, so my ac guy suggested
fujitsu mini-split for 2 bedrooms upstairs, where the central was
not so effective.....if you are not familiar, this is both ac and
heat unit that is put into your wall, with a condenser outside, but much smaller than a standard ac ......
I shut the vents off in the two bedrooms for the central air and use the mini-split alone when I am using those rooms
..... this keeps the bedrooms cool in the summer, warm at night.....and I figure it makes it easier for the central air not
have to cool those two rooms