We are in the process of building a 60'x120'x16' metal building for our personal shop in Central Florida. We plan on insulating and cooling to 76-80 degrees. We won't heat in the "winter". The shop will be located on a wooded acreage. The property currently only has single phase power, but we might consider adding three phase based on cost to install. We estimate we will need a 10-15 ton unit (not set in stone). So if we only have single phase, will need to run 2 or 3 units.

What is the most efficient cooling unit we can install? Geothermal Heat Pump? Split-Unit? What model/brand? Dual Stage? We are more focused on efficiency then cost. A FHP ES 2 Stage Geothermal and a Daikin Split-Unit that is SEER 26 (even though it only goes to 15K BTU) has caught our eye. Also, we are very DIY so would like to do as much of the work ourselves (running geothermal tubing ourselves for example)