I'm going to be installing a Mitsubishi mini split (ductless) heat pump in an insulated shop. The shop is 600 sq.ft. with 10' ceilings, insulated, with about 30 sq.ft. of double-pane low E glass windows. I plan on running HVAC all the time to keep the humidity in check. I'll probably set it at about 78F or so in the summer and about 60F in the winter. In the winter, I'll probably have a unit heater to kick the temperature up quickly and then let the heat pump maintain when I'm working as I'm only a part timer in the shop. I've contacted a few HVAC folks for bids and one bid specified the 16,000 BTU unit and another bid specified a 12,000 BTU unit. I'm in upper eastern TN.
Questions:
1. Anyone with HVAC sizing experience have any words of wisdom on which size to go with? Mitsubishi also makes a 15,000 BTU unit.
2. Now a more Mitsubishi-specific question. The room is 20' x 30' and I can mount the interior unit in the center of either the 20' or the 30' walls. Which would be better? i.e. does the unit throw air wider than farther? If so, then centering it high on the 30' wall makes more sense to me...