A historic heat wave sweeping across California and the Southwest has exposed vulnerabilities in the nation's expanding reliance on air conditioning. San Francisco, typically known for mild temperatures, hit 90°F this week—the first spring day exceeding that mark in years. Similar spikes are occurring in Utah, Denver, and St. Louis, with some regions facing temperatures 40°F above seasonal averages.

This surge in heat has accelerated air-conditioner adoption nationwide, with 93% of U.S. homes now equipped with primary AC systems, up from 89% eight years ago. Experts note this trend reflects both climate realities and cultural shifts, as historically cool regions like the Pacific Northwest now prioritize mechanical cooling over traditional ventilation.