My house has 2 smallish AC units. One controls the kitchen, living room and 1st bedroom. The other controls the 2nd bedroom, master bedroom, both baths and the hallway.
The 2nd unit is giving me just a hint of grief right now. The attic air handler fan is squeaking on it, and I get just a faint whiff of ozone or some sort of burnt electronics if it runs too long or too intensely.
I have a home owner's warranty and the AC folks are coming out to look at the problem, and until then my front unit is doing fine in keeping the house tolerable, augmented by brief runs of the troubled unit.
But:
I'm thinking of augmenting the entire system with the addition of one or two of these Fujitsu ductless units.
http://www.fujitsugeneral.com/wallmounted9-12RL.htmOr... perhaps even retiring the system in the back half of the house entirely and re-running a single duct line from the front AC system to cover the hallway and 1 bathroom (which overlap with air from the master bedroom and bedroom #2).
My master bedroom is perhaps 325 square feet, plus walk in closet and master bath, so about 500 square feet total.
The 2nd bedroom (serves as my office) is 11x15, about 165 square feet.
Two reasons I'm thinking of getting rid of the second unit:
1. It's LOUD.
2. Ducted systems are supposedly less efficient from both a comfort angle and a financial one. I spend 8-10 hours a day in bedroom 2 (my office) and another 8-10 hours a day in the master bedroom, and neither feel as well conditioned as my living room area. All the numbers I see so far are marketing ones and I'm taking them with a grain of salt, but I'm hearing that ducted systems are 25-40% inefficient if the attic is particularly hot and the ducts go through the attic. That describes my second air handler perfectly. The living room air handler is in a closet-like enclosure that services the living room and bedroom #1 without being exposed to the hot attic, and the distance to the kitchen is quite short so less thermal loss there.
Anyone have one of these? They appear to be much nicer than one of the cheapo window units and actually an improvement in efficiency and comfort. Supposed to be able to run at variable speeds, so can operate quietly rather than being either full-blow PITA loud or off like my current system.