13.5 or 15 K BTU AC

I would also recommend a 15k but also have the heatpump in it. We use it to take the chill off on cold days when hooked up to shore power. We have 2 15ks in our 39' 5ver and usually only run one in 90 degree heat. We can hang beef with both running!

I would never even consider the smaller A/C.

Bill

That is a tough call. You would be slightly more uncomfortable on the couple of trips south each summer, but the humidity down there is really low, so the heat is not to bad once you are used to 80F and 85RH. 105F and 10 RH is nothing!

I would say go with a energy efficient 13,500 Btu unit. This is because if you are camping in 30 amp sites, you will be able to run the A/C all day, and not need to stop it to use the 12.5 amp microwave or 12.5 amp coffee maker, or 10 amp toaster.

Running a 15,000 Btu 14 amp A/C you might need to stop the compressor long enough to make coffee, run the microwave, or cook breakfast on a 1,100 watt hot plate.

But with early morning hours, the amperage on the compressor will be less anyway.

I have a 13,500 Btu and a 30' Bounder with decent insulation, dual pane windows. I like the sound absorption of the dual pane windows, and it is quieter inside while driving than the older RV we had. Also less heat gain in the summer, less condensation on the windows, heat loss in the winter.

When I lived in Mesa AZ one summer, it was tollerable to come home to a 85F RV and take a shower. I did not need to heat the water, as the hose was sitting in the shade on 100F asphalt, and taking a 'cold' shower was next to impossible with ground water coming out at 80F and then getting warm on the ground under the RV!

Good luck,

Fred.

Due to the increased ceiling height and volume, a fifth wheel trailer would require a larger capacity air conditioner than the same length travel trailer.

My question would be what generator will run the ac for you. If you are not worried about generators then go low profile, 15000. I have a 29' FW with a new 13,500 brisk air and it works well. Powered with a Honda 3000. I dont know how the Honda 3000 would do with a 15k. My ac owners manual recommends a 4000 gen

If most of your camping is not in the south in the summer, the 13.5 may be the best choice. Again, can be run with generator (get the hard start capacitor). On the other hand, if you will be spending time in my neck of the woods in July, you'll need the 15K. I have both in a 27 ft. box and find I can use the 15K to cool things down quickly and later on use just the 13.5 if we don't want the noise in the living area. The other night, just after Christmas, it was 82 here, I was adding a surround system in the TT and turned on the 13.5, it cooled nicely. But then this was December after all.

I like it cool and get great service out of 13,5k units with a 26'box in the 100+ temps of south Texas summers. I do not have slides which would change things.

15 and get the low profile unit.

In most scenarios, better to have more A/C when needed, especially if you only have 1 A/C. The main consideration is when using a generator, you will need more amps. A 2K Honda or Yamaha will not run a 15K A/C but usually will run a 13.5K.

Go for the 15k.