I have used a Mitsubishi mini-split for 7-8 years and it works fine to cool a 20x20 room during Louisiana summers. Have seldom used the heat. Only 1 warning - I bought the unit on the internet, not from Mitsubishi. The indoor wall-mounted unit developed a coolant leak after a couple of years. Since I had used my regular AC man to install it and not a MItsubishi dealer, Mitsubishi required that I disassemble the unit and send them just the defective part for replacement, which is absurd. I bought a new entire wall-mount unit (the outside part is fine) and paid to have it installed. All things taken into account, it was still cheaper than buying unit from local Mitsubishi dealer. The tech who installed it said they refer to these as disposable units.