how long to lower temps When living quarters at 100

It will take a long time to cool the inside of an RV if the inside temp is that hot especially since the outside temp is still hot and working against the ac units. Measure the air temp at the return side of the unit versus the output side. If the return temp is say 95, and the output side is 75ish then the units are doing all they can do. Not sure where you are, but find some shade!

Hi,

It generally takes a long long time. Consider starting the generator, and running the roof air for an hour before you stop for the day.

Heat soak.....
Walls, floors, cabinets, ceiling, furniture etc etc

Dumping the cool air directly downward will bring temps down quicker due to the volume of cool air

THAT is why when we are traveling in HOT temps......our A/C is on via our generator
Nice to have cool 5vr when stopping for lunch and when setting up at CG


Winter travel...furnace is on

Having a veritable environmental lab's worth of recording instruments on a wall I notice that the humidity must drop before the temperature starts to move downward.
The temperature starts dropping very slowly once humidity reaches 60%. If enough BTU extraction is provided, the temp drop increases once the humidity reaches 50%.
But ceiling and wall Delta T will offset temp gain. The main. Benefit being a reduction in humidity. After I connected an 80-pint dehumidifier the cooldown was faster. But that Delta T and percentage of humidity makes simple calculations difficult.
My casita under construction is going to be firred out in 2x4 with closed cell foam. It's all shaded under a large Parrota tree.
When living in the tropics in a bare concrete dwelling life means the school of hard knocks. My bus cools down much faster at night. I parked it cross ways to the tradewinds.

For a heat soaked RV it is common to take an extended period to cool down. I figure four+ hours after sundown before you feel a chill. Never turn the A/C off in those conditions.

One thing I've done when the sun is just plain unrelenting,where possible....spray the RV down with the hose. I know some places would frown on this but in places where they don't mind, it does help. Wet down the area around the RV too...as in gravel/dirt.

I had a 38 foot class A. My wife choose the outside color (kind of brown and green) and the two 13,500s did not stand a chance of keeping it cool. I upgraded to a pair of 15000s and still not much improvement. Just not enough cool...
I learned to "Siesta" in the afternoons.

2 A/C units for an RV of that size is going to provide minimal cooling. If a 3rd A/C unit is an option it will make a dramatic improvement if you plan to do a lot of hot weather camping. If that's not an option or you don't do that kind of heat too often then running the genset and A/C at least a few hours before arrival will help a lot. I would use the air dump option during travels and then return to ducted A/C when you are going to occupy the unit.

wildtoad wrote:
Measure the air temp at the return side of the unit versus the output side. If the return temp is say 95, and the output side is 75ish then the units are doing all they can do.

At 75 it will take forever. Mine's 55, constantly. I measured it.

I had a small black class-c and even in 120 desert temps with camper sitting all day unattended the AC would cool it in just minutes.
Answers are as varied as are the number of campers out there...