As a contractor, I always caution people against getting "SEER vision". It's what I call the tendency of consumers to focus on only one aspect of an air conditioner unit specs.
Remember, SEER ratings on A/C's are alot like MPG on cars. Everyone knows that the MPG rating on cars is little better than an estimate, a figure arrived at by conducting very specific tests under very carefully controlled conditions. Only problem is, nobody drives their car like the gov estimators do. Hence, very rarely does anyone get gas mileage even close to the MPG rated on the sticker.
Same with A/C's. The SEER rating is a "contrived" figure,if you will - one that is determined in a laboratory under carefully controlled enviornmental conditions and testing parameters. The unit's specs are tweaked to get a certain final figure of cooling out of the unit according to the gov mandated tests. You see the dilemma? Nobody runs their A/C like the gov testers do. Therefore, end consumers rarely get the energy savings that are advertized.
A/C units should be designed - and purchased - with the average end consumer usage in mind, not some gov tests in a testing facility. How old is your house? What R-factor is insulation that is installed? Is it still in original condition, and not deteriorated or collapsed? What are the highest ambient temps/humidities in you area? Don't just take the meteorologists word for it - have them tested at your house. What are you looking for out of the unit? Cold, cold air? Humidity control? Or just enough to cool off the space to a manageable level? Full time or part time usage?
I have many constomers who were sold a such-and-such efficiency unit, because the installer told them they would save electricity. After a year or two they discovered their electric bills actually went UP! And the installers gave all sorts of excuses why what their salesman claimed wasn't happening.
This is with full house A/C's and not mini-splits. But, the same mindset is in operation.
I tell my customers, if anyone calls trying to sell them a high efficiency A/C (claiming they will save 20, 30, or (yes) even 50% on their electric bill), ask to get that savings in writing! You'll find that no one will do that. Try it at the dealer where you're considering that mini-split. See what the salesperson/manager does. I'd bet they'll change their tune real quick, and start squirming in their chair, if you try nailing them down to a guaranteed power savings figure - and they'll pay the difference if it doesn't materialize.
