2nd AC size

Both our prior 40 ft. 5th wheel and our current 27 ft. TT have/had dual ACs. In both, the front or bedroom AC is/was 13.5k. If you're having it added, you could go with 15k but probably overkill for the space. Quieter? Because the space is smaller and it is right over your head, I would say not really.

Seems to me for the difference in price, why not have more than what you might need. You can always run it on low fan. Living in So. Cal it would be a no brainer for me but on the east coast?? Maybe/maybe not!
I guess I'd still say " to big"....

Does your rig have a ducted system that the rear bedroom AC ties into, if so a 15K unit might be more advantageous than the 13K unit as it could assist the living area AC on hotter days. Without ducting a 13K unit along with the dump feature should cool down most RV bedroom areas quite nicely. We don't ever turn our AC units off on very hot days, don't want them to have to remove heat from rig all over again

We have large opposing slides and lots of windows in our main living area, often times the rear AC is set to deliver it's frigid air into the ducting system to support main AC on those blistering days of the year. Survived 110+ degree weather in TX & AZ on dozens of occasions, our AC units endure heavy usage and are also utilized in fan only mode to provide white noise for sleeping.

For a negligible cost difference get the bigger unit.

Noise level is unlikely to be any different.

But if you wind up camping in 100F, I'd rather have too much than too little.

Per Sandia, the 15k will also dump into the living space which the single unit rarely can keep up with. FWIW, no unit is quiet enough to sleep with unless you sleep with shooters ear protection.

Added second air on top of bedroom. Tied into the duct system.

Went with the 15K over 13.5K for nickels and dimes more.


C.B.

Pick the one that is quietest. Both will cool the bedroom.

My last Redwood had 2 @ 15k and it was nice.. the only issue was that when really hot out, with it being 42’, it would be hard to keep up with the heat in n full sun in summer. When in doubt, go with the bigger, you won’t be sorry...

Now, my newer Redwood has 3 @ 15k.. that’s freaking awesome in full sun in summer heat

The only thing I would question over the "bigger is better" folks is, how do you camp? If you frequently dry camp, you may find that a supplemental 9k to 11k btuh unit may allow you to run a little 2000 watt genny to power the slightly smaller ac unit on those occasions you dont have a shore power tap available.

I would recommend the larger 15K... The reason for this is that no matter how hot it is now it's getting hotter and hotter and hotter every year over the last several years has set records for "hottest on record" and you will be needing the added cool.