What temperature should I set my pool heater to for the best balance of comfort and cost?

78°F (25.5°C) is the sweet spot. It’s warm enough for most swimmers but cool enough to keep your heater from running constantly. Every degree above adds 10-30% to heating costs, so if you think “it’s fine,” you’re saving money. For energy savings, use a cover at night to cut heat loss by 50% or more.