Upgrading AC Unit from 13,500 BTU to 15,000 BTU

[rockfordroo]

Originally Posted by myxkp

Apologies for the misspelling. Auto complete got the better of me. It is properly spelled Psychrometric.

Spell check likes it either way!

[JohnD10]

Originally Posted by myxkp

Too many BTU,s is not good. Removes sensible heat faster than latent heat leaving high moisture behind. Look at the psychometric chart - this is the science behind sizing a/c units.

I doubt that the moisture thing is the issue...

I'm guessing that most decent size TT's or 5'vers with 30-amp service come with only one AC unit for two reasons.

The first...cost!

Cheaper to make the unit and a more inviting price for the end consumer (ie.- us).

The second reason would be that pushing a 13.5K AC on a 30-amp RV is already pushing the limits of the electrical service in the RV.

Try running a coffee maker, microwave and the AC unit at the same time and guess what typically happens?

Or just the electric water heater and AC together...

POP!

My 33-foot 5'ver has a 13.5K AC unit and 30-amp service, and it can barely keep up once the temps get over 90 degrees.

I live and travel the southwestern US of A.

Now I live in Yuma, AZ (after 26 years in Denver, CO)...it is 8:05 am right now and already 92 degrees outside.

I believe that a 15K AC unit would be better, but would still struggle with the heat.

And would probably pop the circuit breakers in the 5'ver.

[Bluepill]

Yeah, my 13.5K BTU Dometic pulls 1670 watts per factory spec. sheet. (Also a lousy EER of 8.1 compared to window units in the high 11's). That leaves precious little extra for the converter and microwave. Using the 80% of maximum circuit capacity rule for steady loads results in a limit of 2880 watts for a 30 amp. service.

15K BTU is only an 11% increase in cooling capacity over the 13.5.