Cityboy said:
I'd buy a 10 SEER in a minute if the price is right. The manufacturers make claims of the massive savings you will get because of the increased efficiency; but the likelyhood of the ROI (actual savings on your electric bill) on the super high SEER units over the life of the system is small and most likely nil. Best to go with the standard system in most cases unless you are the type of person who wants to own "the best" and really like all the bells and whistles.
Agreed to a point.
With a ductless mini system, savings would be minimal most likely in the SEER rating difference, but as mentioned, you would be surprised on the cost difference (nowhere near residential conventional duct systems). Variable that I would look at is the price of R-22 compared to R410 and where those prices will be in the future, along with parts availability. Most if not all ductless systems are made overseas. If the parts are not in the U.S, you may have to wait (had a Sanyo compressor bad after 4 years, had to wait over three months for it to come it, to the point where I was tracking it on the boat in the Paciffic).
Manufacturers of ductless mini systems are nortorious at times for lack of parts availability on "older" units at times.
Since Bob is using this system for his garage, used part time, and if system for whatever reason should fail, seems like no big deal.
However, with conventional systems, match-ups, availability will play a part in the SEER rating "game" and the ARI match-up.
Scenerio. Possibility that a 7 year old sytem either has the condensing unit or coil "go down" (bad). If by chance you can find a 10 SEER rated replacement for either coil or condensing unit, hey, you're good to go. But...if the other piece of equipment should fail in the future, you may be STUCK with going with a new complete 13 SEER new system and even though you replaced one piece two years ago, now have to buy another complete sytem so they (condensing unit and coil) will actually "work" with each other.
Yes, at times depending on the coil, outdoor unit, SEER rating, you may "get by" with mixing an unapproved matchup, but, big but, you replace any outdoor unit without a manufacturers APPROVED matched indoor unit (or vise versa) you voided any warranty on the new unit (and they do check model # and serial number, which is whats needed for warranty info).
You could litterally put in a new 10 SEER condenser and just voided ANY warranty depending on the indoor evaporator coil.
Now, that being said, with a split ductless mini system, you get a 10 SEER system and need to replace either the evaporator coil or condensing unit, you may be stuck with no option, due to availability of either unit.
Keep in mind, what Bob buys really is of no interest to myself, only trying to point out the possibilities and scenerios.
However, a decent HVAC contractor should explain all of your (as a homeowner) options and why.