20 degrees refers to the output cold air in relation to the input hot air NOTHING TO DO WITH AMBIENT OUTSIDE AIR TEMP. So, you get your hot RV and it is 105 INSIDE. You start your AC units and the air running thru the evap will be 105 degrees and the output at the vents after running 15 minutes will be 85 degrees. AS the RV cools down the input and output temps will be 20 degrees. The RV starts to cool down and it is now 100 degrees in the RV. Odds are the 100 degrees is now the INPUT and the cold air output will be 80 degrees. The downward COLD progression will continue at this 20 degrees until the unit has reached its max low cold air output depending on the outside Heat and Humidity and how well the RV is insulated. Doug
