In order to determine what size solar kit is appropriate, you must first define the total load to be expected of the solar power system. Most manufacturers will publish a specification sheet of the AC unit online and will include a nameplate sticker on the AC body. Both can be used to determine the actual power rating of the AC. BTU is a common measuring unit for energy in AC and water heater products, however we are intrested in the energy rate, or simply power. Power will be listed in units of Watts, and can be used to determine the total load resulting from running the intended AC unit. Multiply the power rating recorded in watts by the total number of hours of operation intended, to obtain the total watt-hours. Divide the total watt-hours by the peak sun hours in the location of installation, and multiply by a safety factor of 1.5-2, to obtain the total number of watts your panels should produce to power the air conditioner load. The total power load can be divided by the power output of one panel to obtain the number of panels needed.