Answer
Mar 10, 2026 - 02:28 PM
It is generally cheaper to shut off the pool heater at night and restart it in the morning, even if the pool temperature drops 10°F. Keeping the heater on all night wastes energy, because the pool continuously loses heat to the cooler night air, requiring the heater to work harder overall. Reheating the pool in the morning uses less energy than maintaining a constant temperature overnight.
