Will getting a larger roof A/C solve the problem?

Dale.Traveling wrote:
Certainly, but before making the plunge check a few things.

1. Take down the lower unit (the ceiling fixture inside the coach) and with a flashlight check the fins of the interior heat exchanger. Even with the air filters a lot of debris will get past and coat the fins and degrade performance.

2. Get up on the roof and remove the cover. Clean the fins and the external unit plus check the fins. If the soft aluminum fins are bent do your best to comb them as best as possible.

3. As best you can seal the interior duct work. While doing #1 above check to ensure minimal leakage between the intake and exhaust. Use aluminum tape to seal.

I have the same thoughts as Ivylog with regards to a heat pump. A heat pump will cost more but will give you more flexibility for year round camping. Replacement is pretty simple and the hardest part is getting the new unit up on the roof.
A/C has two purposes. First is to condition the air which is pulling the humidity and second to cool it. If you over air condition and get the temperature down faster than the humidity you'll end up with a coach that feels like a cave. Cold and damp.

X2. There is nothing magic about a "new a/c unit" for cooling. A/C units use compression and expansion of gas to cool. So long as the gas has not escaped the unit, the compressor still compresses, and the blower still blows, then it's debris and build up on the unit that will cause it to cool less.

They sell a/c fin cleaner at Home Depot. It's great to use. Clean EVERYTHING up. Take off the shroud and remove any debris.

I've seen A/C units cool excellent that are 30 years old so long as they are kept clean!