One of my friends who lives in Mexico in a house with no central heat/AC got the ductless high wall air conditioners - 1 for the great room/kitchen and smaller ones for each bedroom.They live near the ocean and don't have to use them all the time and they have a back up generator because their power goes off fairly often. They have found it's lots cheaper than the central AC they had in their last home because they only turn the bedroom ACs on a bit before bedtime and have them on a timer/thermostat so they shut down after a couple of hours.