I just purchased 2 split a/c systems as an upgrade from the units I currently have. It is now September 22, 2014 and I am unhappy with my 3 month old brand new units. I started with a Fujitsu 11000 btu in the master bedroom and a Mitsubishi 30000 btu in the living room. The Fujitsu was weak in cooling efficiency and even though I cared for it very well it required cleaning and servicing every 6 months. The living room was an older model - but if you set it at 71 degrees - we'd be freezing within the 1st hour. Both eventually had freon leaks. I replaced the bedroom with a 2014 Mitsubishi 15000 btu thinking I could run it on a low and quiet fan setting at night. The living room was changed to a 36 000 btu 2014 Mitsubishi which I was also hoping to run on a quieter setting. But - NO! We are running both of these units on MAX 59 degrees on a high fan to cool either room which takes a couple of hours. The air feels cold coming out of units - but not too far from the units. Recalled the installers and checked the freon, temps, and the workings of these. 2 month old units. "everything is Normal". Tech says that's how these new energy efficient units run. He says you gotta run them on max to start with or before the house heats up during the day or close the doors down the hallway to trap the cooler air in the living room. The bedroom is the same - we sleep at 9pm - so we run it at 7pm - on MAX!! It sucks - in Hawaii both units plus the install $6200. My electric bill is slightly higher because these energy efficient units run longer and on Max!!! So disappointing! I have tried different temp settings and combinations of fan power. Some have suggested that in Max mode- it is bouncing the cold air off the opposite wall back to the unit causing the thermostat to raise the temp. I am baffled - so junk !!!

Thanks for your help, zL700; I like your link for SlimDuct enclosure, much better than my idea for 3"-4" pvc pipe! I plead guilty to a LOT of sharing! Once one reads all the way to the end, my question in the first line was 'history' : "Can anyone support my argument that it is ample to use a dual split unit for just the front two bedroom's? " This would save both cost and a difficult condenser install location. In short: We have a MrSlim MSZ-A17NA single-split 17 Kbtu unit for the 3rd floor finished attic, and a conventional 28 Kbtu ducted unit on the first floor. Our calculated 50 degree day heat loss for the entire house is 48 Kbtu, of which the two rear small bedrooms are only 5 Kbtu each. I have agreed to put in a dual-split 9+9 or 12+12 for the two 2nd floor front bedrooms. Shouldn't this effectively cool the entire 2nd floor? I need technical, experienced opinion to support my desire to avoid having to put in a 3rd condenser in the larger of the two rear bedrooms. Thanks to All - - Old Salt Details were dated SEP 3, 2307 hours.

"Yes but is the explanation, "the wire vibrate in the conduit" reasonable. Can this even occur?" When the unit starts up the first surge of current is up to the "LRA: 68 amps". LRA is 'Locked Rotor Amperage." Since the motor is NOT turning yet, it pulls a large current surge for a few cycles of the 60 Hz power. This CAN cause wires in a metal conduit to move around. It is less common in non-metalic conduit. It is not a problem. As long as the unit starts up without tripping the breaker, and starts up quickly (no more than a second or two) it is fine. The current will drop to the "RLA: 14.1 " value or less so quickly the breaker does not trip.

The system I am considering is the Mr Cool DIY 24K mini-split. I have no idea how it compares to bigger brand names, but a professional install is simply out of my price range. I'm very experienced with construction, plumbing, and electrical (we built our own house), so the DIY aspect is inviting also. Finding workable locations for the indoor and outdoor units has been the biggest hurdle. We have a small house but there's very little space that isn't already being utilized with windows, cabinets, lights, etc.. We don't really use the space between the house and garage anyway, so putting the outdoor unit there would work out great if the clearances are acceptable. I also have plenty of room to move the unit side-to-side, so I should be able to avoid the coiled up line set so common with Mr Cool installs.