I am looking at the options of installing a ductless mini split heat pump (18000 BTU) and was given 3 options:

1). Wall bracket - lowest cost one but may have vibration/noise issue according to the contractor
2). Concrete slabs on the ground - recommended by the contractor but highest cost because of the amount of the work
3). On my wooden porch - may have noise issue because it will be closed to my living room window

The porch option seems pretty good to me because a. it has a roof so the unit will be protected against snow/rain and b. because it's already perfectly level so it cost less than option 2. As to the noise, I think it should be all right because it's at least 1 feet from the windows and it's my living room, not my bedrooms.

Am I correct? I would appreciate any comments.

Thank you!