In many locations, homeowners can significantly reduce their air conditioning use by installing a programmable whole-house attic exhaust fan with an insulated ceiling damper. Open some windows & run the fan after dark to flush heat out of the attic. Then run it again from 4 to 7am before closing windows & shades during daylight hours.
UCLA researchers developed a passive cooling technology for buildings to reduce reliance on AC. They manipulated radiant heat transfer at ground level, claiming that the new method is a sustainable answer to temperature regulation, with potential to bring down energy consumption. Cost-effective materials like polypropylene were used in the process.