How big before 2 A/Cs are a must?

I don't think it's all abut the size, I think it's the outside temperature, if you are under shade, if the camper has forced air from the AC only, or ducted, and how well built and sealed the camper is. Lots of factors. But definitely, more space means more BTU's.

DutchmenSport wrote:
I don't think it's all abut the size, I think it's the outside temperature, if you are under shade, if the camper has forced air from the AC only, or ducted, and how well built and sealed the camper is. Lots of factors. But definitely, more space means more BTU's.

hes asking about Class A MH not a camper big difference
34 ft in real hot climates need two AC for sure

I would say no. We have a 37 with two and live in New Mexico but travel around and three are a must.

I think you will be disappointed if you only have 1, especially if you spend most of your time in the south during the summer months. I had an 1994 32ft Class A with 1 and it was difficult to get the bedroom cool enough to sleep. I ended up adding a second unit in the bedroom vent. Way better!!! Have no issues in my 36ft unit with 2.

We have a 34' 5th wheel ......well insulated and the 15K btu A/C can maintain comfortable temps in 100*F

But 90*F and HIGH Humidity and it lacks cooling

TWO 15K A/C Units would be preferred in SUMMER temps where there are HIGH temps and/or high temps with high humidity

Don't always have to run both...but is nice to have when needed.
With only ONE it has to RUN & Run & RUN & Run

In an RV, it is best to get two of everything, so one will work while the other is broken. ;)

We have a 30 footer with 2 a/c's. Well insulated too. One is not enough.

Most of our RVing was done down at Corpus Christi where it is hot and humid in the summer. We had two non-ducted A/Cs, but only ran one at a time. Daytime ran the rear pointing to the front, kept the living room and kitchen cool. Nighttime switched to the front pointed to the bedroom keeping it cool at night.
It also cut down on the noise so we could sleep or watch TV.

My MIL has a 32' with one 13.5K and it struggles in the Midwest summer heat.

Our 36' has two units, one 13.5K in the bedroom and one 15K in the front living area, ducted throughout the unit. With both running wide open and an extra fan blowing on the floor in the dead of summer here in NC under moderate shade it is difficult for them to keep up to my satisfaction during the daytime. They do cool off the RV pretty quickly after the sun drops, though, and is usually very comfortable for sleeping. I'm considering upgrading the bedroom unit to a 15K to help out.

For me, if the RV was anything over 28', I'd want dual units.