VFDs and inverters are nice, but have you ever looked inside of an AC unit with an inverter and asked what it would cost if the electronics has a problem? Simple dumb single speed stuff looks like it costs more to run, until you have a problem, which you will. On simple single speed fridges and AC that don't do anything special maybe you need a motor cap or motor or something every parts house has for little money and easy to swap; the moment you introduce more complexity is the moment you bend over for GE or Mitsubishi or Samsung to gouge you for basically any part.