My attic in our old beach house is an open space with beds. The attic has no insulation. The attic is used maybe 6 times a year for overflow guests. I presently have a window unit. Due to the salt air, the window unit only last about 5 years. It is time to replace the window unit. Would a mini-split unit work in this space? Temperatures range up to 100 degree when the AC is not on. What are your thoughts on a mini-split unit for this space?