I'm afraid your predication may be correct about the cooler weather. We have only had two days so far this season that our temps have been in the 60's. Our previous fifth wheel was a Cougar 327RESwhich was 36. Something feet. It also had a 30 Amp service with one 15BTU AC. We never had a problem with that one being too warm although we never went out of the U.P. Of MI with it. The new Jayco we bought again was 39.5 feet with dual units. We would run the 15 durning the day then in the later part of the day would run the 12 in the bedroom which kept us comfortable in the living area, plus without all the noise above your head. My wife really doesn't like AC unless it's really hot and dislikes the noise immensely. She has that ear ringing thing so that just adds to it. With that in hand I'm thinking we will be fine. I like the idea if we do need to add one of running a separate cord to the post. I did that in the Cougar we had when I installed the fireplace. I added a waterproof outlet on the out side so I could run a separate line to the Elec. Post but also had a switch inside whereas I could unplug the F.P. from the separate line and run it through the fifth wheeles Elec. Service. I like this Forum already, so good to get feed back from folks out there using these products. I'm going to start a post to see if anyone else has the model we are thinking about purchasing. Thanks.