I'm seeking brand recommendations for a window AC unit for a 12'x18' (216 sq ft) workshop, with open stud walls that have been insulated. My primary requirement is a quiet unit, along with suggestions about the feasibility of AC/Heater combo units.
If you want quiet and efficiency, consider a mini split instead. It will, however, cost more.
you can purchase heat pump window units.
cools in summer action reverses to heat in winter.
cost a little more, but works well.
probably cost you $500.
p-tac unit could also work. and is available in hp also.
mini split is quiter, costs less to operate but
is a sizable cost for a 216 sq ft shop.
you should do some air sealing to make it
easier and more cost effective to condition the space.
best of luck.