I put a $8,000.00 Mitsubishi mini-split (which is like the Sanyo in the link above, only quite a bit larger capacity) in my studio control room and I'd say right up front that any of these mini-splits are definitely NOT quiet enough to have on when working in your control room and needing to use your ears.
You're essentially bringing the air conditioning condenser, fan, and associated air turbulence directly into your listening space.
Having said that, they are inexpensive compared to a full blown A/C system, and if your geographic area isn't one that suffers 100 degree days in the summer, then turning off the mini-split while you're working might be a viable option.
I'm definitely NOT in a hot area of the country, so my mini-split can be off for a few hours on a "hot" day and the room remains stable temperature wise.
If you're in an area that gets extremely hot or humid days in the summer, and if you work in your suite even close to all day, then these may not a good option.......they ARE noisy, and if they're off all through your work day, your room's going to get too hot.