[gsquaredxc]

You can reason it out (in a way that might make Fermi proud) pretty easily: a very large AC unit can be powered by a very small (relative) solar panel, where the solar panel is maybe 20% efficient. Thus, solar irradiation is substantially higher than AC power usage.

[vanviegen]

That's only accounting for the energy the airco unit consumes. What the airco unit does is remove heat from the inside of the house, and dump it outside. That effect is about 4 times larger.