I bring a 5k BTU window A/C as an emergency spare. I’ve tested it out and found it not quite adequate. It struggled to try to cool my camper, while the roof air had no problem even out there in the desert.
Interesting..I bought this 5K model to cool my 30' travel trailer bedroom so it has been hardly used..It blows really cold air and does a great job on my 9.6 Lance..
Maybe brands makes a difference, yet my son just bought a new off brand 5K at the local lumber store and it also blows super cold air and blast his lady out of the bedroom..To cold according to her...
I replaced the 13.5 btu Coleman that was in my last Lance 8.6 camper with a new Carrier 13.5..What a mistake,way to big for a small TC but money talked at the time and it was a few hundred cheaper than the smaller rooftops.
Funny how something works for one camper and the same thing doesn't cut it for another.