Are 5 rooftop a/c's really necessary?

[luvrbus]

I have 5 roof tops on a 45ft bus I never ran all 5 yet but 3 sure did a good job setting Wed in the 120 degree heat plus 3 is all you can run off 50 amps lol but it was nice to know I had the 2 extras if needed  

[CrabbyMilton]

Well some buses have many small sections so that way each room can be controlled separately. Either way it's really a "cool" bus.

[belfert]

I've run our roof airs in 107 degree heat and they never shut down on us. I'm wondering why they shut down in certain cases and not in others. Another thing we did once in Wisconsin when it was over 100 degrees and we only had 13,500 roof air, was during the hottest part of the day, I took a garden hose and watered the roof of the coach and set the hose nozzle in such a way as to mist the roof top a/c cooling fins. Made a difference and got us through the week of over 100 degrees in a bus with just one tough little Coleman 13,500

Almost without fail the A/C units would start to shut down around 4 pm every day as the heat peaked.  It was 107 degrees in the shade and warmer in the sun.  The 20 amp breakers would trip or the A/C units would just shut themselves down.  I do have 12 gauge wire to the A/C units.  We were boondocking in the desert so no water to spray on the A/C units.

Swamp coolers would have been better if we had the water to supply them.

[Lin]

The only time we had a problem with an AC refusing to work was one summer on a trip that got to about 130 degrees!  Not even the dash AC would work.  What is the make of yours that shut down at 107? 

[RoyJ]

Makes me wonder if they're better off getting a reefer unit off a 53' trailer. After all, those thing can chill an entire trailer load of ice cream down to 10 degrees in the desert...

[belfert]

I have Atwood, Carrier, and one other brand of of rooftop A/C unit.  They all had issues, but the Carrier less so because it cools a smaller area.

A trailer refrigeration unit would be heavy, noisy, consume a lot of diesel, and not be designed to keep a space at 72 degrees.  Such a unit would probably be so over sized that it would not properly dehumidify.

[luvrbus]

Weak breakers,all ac units the amp draw goes up in 100+ degree temps plus the generator output drops

[John316]

Yes. You need five, depending on your build. We put five, on Clifford's bus, because it heats up. Sitting in 120d weather needs three. However, now try driving in 120d. You will be using four, if not five. We built that bus so we would always be comfy, no matter what. -30 to +120. Been there done that.

[luvrbus]

And you did a good job John we are amazed how easy it is to cool  .I do not understand the concern about the seer and amp draw on a AC unit in a bus which is a RV not your house or home unless you full time.
We just buy fuel for the generator or plug in at a RV park and let the park pickup cost of the electricity to me the seer and amp draw is not that important unless I am missing something lol which can happen

[Darkspeed]

I am concerned because my bus (when complete) will be my full time home and I always strive to be as efficient as possible anyway.
This is one reason im putting so much effort into insulation and thermal isolation on the rebuild.
I know there is a growing trend, especially in my generation, toward the Bus Home & Tiny Home full timers.

We need a new designation, HV? RV = Recreational Vehicle , HV = Home Vehicle?

[Iceni John]

I am concerned because my bus (when complete) will be my full time home and I always strive to be as efficient as possible anyway.
This is one reason im putting so much effort into insulation and thermal isolation on the rebuild.
I know there is a growing trend, especially in my generation, toward the Bus Home & Tiny Home full timers.

We need a new designation, HV? RV = Recreational Vehicle , HV = Home Vehicle?

Residential Vehicle?   (That's actually the idea of someone on another forum.)   Or how about COW  -  Condo On Wheels?

John

[belfert]

The breakers in my case were practically new.  I was using some of those two breakers in one slot for the A/C units, but I rearranged things to run the A/C units off full sized breakers.  I really need to replace the breakers as they have tripped too many times now.  I will be doing a minor rewire that will include getting rid of the double breakers and new breakers for some of the circuits.

[Nick Badame Refrig/ACC]

Hi Guy's,

We install 5 roof airs on entertainer coaches for 2 reasons:

1-  Most entertainer units only have dash air so, going down the road gen-sets are usually humming
to run as many roof airs as possible to keep the cabin areas cool.

2- Redundancy... A leasing company would not want to have a coach out of commission because of
an A/C unit failing while bands are at a concert.

There is no such thing as too much A/C
Nick-

[TomC]

There is also a big difference in having ducted A/C or the old style hang down direct discharge type. I have three direct discharge old style Coleman 13,500btu. Usually only need 2 going down the road. Was in 108 degree weather once and kicked on the third-only to have my wife wearing a sweater. Nothing better than having old style mechanical thermostats that rarely go out-mine haven't in 21years.
The big difference is insulation. I have 2.25" of sprayed foam insulation. Also, the windows. When I had the original bus windows that rattled and leaked air, it was hard to keep the bus cool. Then had custom Pen glass windows made. Even though they are only single pane and lightly tinted (like to see out even at night), they are very tight and quiet. So much so, I have to keep the roof vent open in the bathroom at all times otherwise with all windows and vents closed, when you close the entrance door, it pops your ears. Good Luck, TomC