Since this video is an hour long, the result of digging a small bore hole and routing water pipes through, and hooking those up to a slightly modified window AC unit resulted in a 250 to 300% increase in overall cooling efficiency, and effectively turns a 5000btu air conditioner into a 15000btu unit, but with less power draw than an unmodified (control) 5000btu unit.
I saw an earthship design that instead of AC, had a solar powered fan from a long underground pipe to bring in cooled air.
That’d be a good option for people in arid climates where there’s enough space to construct one.