Dehumidify mode and shutter strategy cut indoor heat in summer

Using the dehumidify (Dry) setting on an air‑conditioner reduces indoor humidity, allowing the compressor to run at lower power and making rooms feel cooler even when the temperature display remains unchanged. The method relies on the fact that moist air feels hotter than dry air, so removing excess moisture improves comfort without the energy cost of full cooling.

A complementary approach, long used by people born between 1960 and 1980, involves keeping windows and shutters closed during the hottest part of the day to block solar radiation, then opening multiple windows at night to create cross‑ventilation. This night‑time airflow draws heat out of walls and furniture, lowering indoor temperatures by 4 – 7 °C compared with the outdoor heat. Dr Pierre‑Louis Toutain explains that “the human body needs a nighttime thermal drop to activate” restorative processes, underscoring the health benefit of the practice.