Geothermal air conditioning units offer the most energy-efficient cooling option of all the various air-conditioning options, but it’s fair to note that it can be quite costly to set up.

Mini-split AC unit installation cost varies by type, size and number of HVAC zones. ... Floor-Mounted. For between $1,300 and $3,700, homeowners can install a floor-mounted mini-split AC.

Also known as ductless mini-split air conditioners and heaters, they consist of one or more wall, floor, or ceiling-mounted indoor units connected to an outdoor compressor.