I have a Ford Econoline Van E-150 and I built a 30 amp distribution that works great for Refrigerator, TV, Microwave, and Heater in cold weather. Interior approx 6' x 22' = 132 ft2 with 4'8" ceiling. Found a 14,000 BTU 14.8 amp A/C at the Thrift Store, but it only cools maybe 5 degrees on 90+...