In 2023, Princeton researchers tested radiative cooling, keeping a building 3.9°C cooler

Researchers tested a building's ability to stay cooler than outside air naturally. A special roof released heat towards the sky, while airflow moved air through openings. This passive system kept the test box significantly cooler than the prevailing outdoor temperature. The experiment demonstrated radiative cooling working with thermal mass and temperature-driven ventilation. This approach offers a way to cool buildings without mechanical systems.