Three experts said the best balance of savings, comfort and humidity control is to raise the thermostat a few degrees while away, rather than keep AC blasting all day.
U.S. Energy Department guidance says shifting the setting by 7-10 degrees Fahrenheit for eight hours a day can cut annual heating and cooling costs by up to 10%; each 1-degree increase can trim cooling costs about 3%.
Humid climates make fully shutting AC off riskier because moisture can build up and mold can form, while restarting after hours off can also add wear since systems may need 15-30 minutes to run efficiently.
Savings vary by home and equipment: drafty houses heat up faster, window units are generally less efficient, and smart thermostats can automate setbacks and deliver about 10% savings.
Simple steps such as closing blinds, using reflective shades or window film, and opening windows at night in dry climates can further reduce cooling demand.