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As with many people on the forum I am interested in increasing the performance of the air conditioner system.  The first thing I thought of was to collect data. So here is what I did.  I have 2 two speed units that are from the factory with original thermostats

It was late afternoon when we started the test (4:45), and collected data for 1hr 50 min.  The data I was collecting mostly was bedroom and salon thermostat and duct exhaust temperatures on a regular basis to plot the cool down rate. Midway through the test I decided to start recording the carpet near the A/C inlet in the entryway.  I also collected the power usage delivered (5400-5200W on high) during the entire test.

It was only 93F outside when I started the test, nowhere near the hottest temperature it gets to in Phoenix.

Here are some of my notes as I would summarize them, but I don't know if this shows the system is good or not:

1. I am guessing that the a/c units are working well, but never were cold enough for Phoenix.
   
2. The coach did not change power consumption much during test but was lower as the temp dropped inside.  
   
3. Prior to testing, I checked power consumption of each unit.  They drew about the same power.  My guess is the performance is about the same for the 2 units.
   
4. As the indicated thermostat temp dropped, the duct exit temperatures continued to drop as well.  Always staying at 30-35 degrees different between thermostat and duct exhaust temp and 20-25 degrees between inlet carpet near the step and duct exhaust.
   
5. Because of the location of the thermostats (front mounted on outside wall next to passenger seat, back mounted closet wall interior wall) the front thermostat gets heat from outside and will normally be very different.  During test however the exterior next to thermostat did not pick up that heat as it was in the shade the entire time so started out warmer than the back thermostat but ended up about the same.
   
6. On low setting, the temp started to rise, but I only did it for 10 minutes at the end of testing
   
7. During the entire test, the temperature continued to drop, so the coach would have gotten cooler with more time.  It is likely when I anticipate needing air conditioning I should turn it on several hours in advance to precool as much as I can.
   
8. Temp inside seemed acceptable, but we were not at 115 and heat soaked from the engine running.  At these conditions I know it gets and stays uncomfortably warm.
   

So what could someone do to improve the cooling?  I know that it has been a while since I cleaned the inlet filter and I plan on doing just that to start.  In addition:

1. Possibly changing out a vent for a roof 48V AC would increase cooling capacity. It might be fairly easy to vent out of holes next to refrigerator.  
   
2. I think I saw somewhere that putting a fan under the coach helps with lowering temp under there to increase heat transfer on the outside unit
   
3. Rip the whole basement system out and replace with mini splits like some of the adventurous gurus have done.  Lots of nice work out there.
   
4. Looking for suggestions
   

Thanks for taking the time to read, I look forward to comments

Glen

Glen, nice work. 

A couple of questions, have you done anything to the units? Charged them up? Pulled them out and cleaned the coils? These are some options as well. 
Really it also depends on how you plan to use your coach. If you are going to be doing more boondocking you may look into one of those other options. There are quite a few DC air conditioning options out there. I have a buddy that put the Cruise and comfort dc system on his bus and he is quite happy with it. He said they were very helpful in helping him figure out what would work best for him. I am thinking about this as an option, I really thought it was going to be expensive but really they are comparable to the cost of a roof AC now. 

https://www.cruisencomfortusa.com/

Here is a video of an install of this system, may not be the best install out there but it gives you an idea:
https://youtu.be/NZJGYYkSa_w?si=mNCnAfCgk2ajX3n3