File PC: UH MānoaUniversity of Hawai‘i at Mānoa atmospheric scientists found that the century-old yardstick used across many industries to estimate air-conditioning and refrigeration energy demand—called cooling degree days—is missing something fundamental. Challenging an old assumptionEfficiency and energy demand of cooling was assessed across the US. They applied this new cooling demand metric to 50 years of high-resolution weather data (1971–2020) across North America to quantify how climate-driven changes in cooling efficiency have already reshaped cooling demand across regions. “Getting cooling demand right isn’t an academic exercise; it directly affects how we plan, size, and operate future energy infrastructure as the climate changes.” In humid regions, heat and moisture compound each other, so the energy burden is worse than temperature alone would suggest.