Time-of-use rates
Cleanest and cheapest are not always the same hour.
Most U.S. homes pay a flat price per kWh, so moving a load changes its CO2 but not its cost. Some utilities offer time-of-use plans with a higher peak price, often on weekday afternoons and evenings. Your bill or your utility's rate page lists the hours and prices.
Enter them under "Cheapest hours" on the dial. Each run then shows its cost at your usual time and at the best time. If two hours are equally clean, the dial picks the cheaper one.