I'm an HVAC installer / service tech since 1999. The "mini-split" equipment is almost like magic! It's rediculously efficient and quiet, low maintenance equipment (when properly installed). It's been all over the world forever, but like european fashions, it took a while to hit the U.S.
I can only speak of the mitsubishi and the fujitsu equipment (I've taken the full install and service courses on both), but I'll tell you what I know...
-The newest units are good to -20F for air-to-air heat pump, that's almost unheard of!
-Fujitsu runs a "simulated 3-phase compressor" higher volts = lower amps = more efficient!
-The systems are about as efficient as you can get ( they usually get double the standard split - system {ductwork} seer ratings).
-They are "load sensing" indor units, monitoring the intake and exit air temps and modulating refrigerant flow thru electronic expansion valves (EEV'S), and with the fujitsu's VRF (variable refrigerant flow) systems, you can connect up to 8 indoor units to one outdoor unit - AND THE OUTDOOOR COMPRESSOR NEVER WORKS HARDER THAN THE LOAD DICTATES! minimal wasted energy versus the "standard home's" forced-air heating system that usually runs at 100% or 0% (some folks go for the two-stage furnace {60%fire or100% fire- figure a 100,000buth furnace low fire =60,000buth and hi-fire =100,000} - these modulate from about 36% - 120% YES! THEY ARE RATED TO AND CAN PRODUCE MORE HEAT THAN THE NAMEPLATE RATING!!
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-These things are damn near silent during most normal operation.
-Great for smaller houses or places that ductwork won't do.
-Different designs of indoor units (wall-hung, floor standers, drop ins for grid ceilings, even picture frame or mirror type units!)
Obviously, this type of equipment will be more of an initial investment than your traditional HVAC system, but I can tell you that over the years, more and more people are starting to come around to this type of heating and cooling system, and NOBODY has complained about operating costs with these mini-splits. If you want to hear some horror stories, read up a little about when Geothermal heating systems go down, or about their operating and maintenance costs versus mini- split. I've actually had people ask me to rip the Geo out of their house so they could burn natural gas again!
One thing I see over and over with the mini-splits is happy customers
Thanks,
Victor