Best cooling and heating option quad-plex

[John Carbone]

Have a quad-plex of 4 1 bedroom units (500-600 square feet each). The current setup has 2 central a/c units which is not ideal. The units are old and need to be replaced. I’m looking to have 4 separate units in each of the apartments so each unit can change their heating and cooling independently. I’ll be covering the electric bill so not worried about that.

what is my best option in the south?