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.
probably $800

mini split is quiter, costs less to operate but
is a sizable cost for a 216 sq ft shop.
cost $2500

prices approximate.

you should do some air sealing to make it
easier and more cost effective to condition the space.

best of luck.