Mother in-law got the owner on her place to pay for the system if she was to pay for the install, cost her around $300 to install, owner had it all done within a few days he saw it as an investment.
Most owners of units haven't been in to see them in summer or ever (aunty has never been to her investment units since purchase) its good feedback for them to know if its really hot in summer in the unit or not, and most people just don't complain because they are in a rental.
Have her contact the realestate and ask if the owner can have aircond fitted, its only a question at the end of the day, its either yes or no and really doesn't hurt to just ask.