Chunker, I use a freestanding unit like you in the Texas heat (100+) and it does the trick. I vent it out the side window of our large slide. I have a 15k and 13.5k a/c units like you. One option is to go to a 15k a/c with heat pump and replace the 13.5 unit. Your stand up unit is a MUCH more economical solution if it works for you. I only use the stand up unit if it’s going to be above 93 degrees. In lower temps I take out the portable. The portable really helps to cool the rig down quickly and keep it around 74 inside. Thankfully it’s also a quiet unit that vents moisture/condensation out the vent. I do have a drain hose that I put out the bottom Of the slide but have only seen water drain once on a really humid day. Happy trails.