For light-colored (or reflective) and insulated teardrops, 2500 BTUH should be enough.
Shadow Catcher wrote:I ran our 2500 BTU pet cool one a 90+F day with the tear in partial shade and with no one inside could not get the cabin below 78F.
Our experience is different with the PetCool. We don't usually camp in the summer, but did so one time with friends that had a pop-up. Daytime temperature was around 100 degrees. Out PetCool was working hard but kept the teardrop around 80 degrees. With nighttime temperature in the mid-80s, the PetCool kept the cabin at 68-70 degrees. The probable reason for the difference is that our PetCool is permanently installed, supply and return lines are insulated, supply and return are separated for "flow through" airflow (supply is at head of the bed; return is at the foot of the bed) and there is an additional inline blower to help the return flow back to the PetCool.