R403.10 Pool and Permanent Spa Energy Consumption
Time switches or other control method that can automatically turn off and on according to a preset schedule shall be installed for heaters and pump motors. Heaters and pump motors that have built-in time switches shall be deemed in compliance with this requirement.
Outdoor heated pools and outdoor permanent spas shall be provided with a vapor-retardant cover, or other approved vapor-retardant means.
Exception: Where more than 75 percent of the energy for heating, computed over an operating season of not less than three calendar months, is from a heat pump or on-site renewable energy system, covers or other vapor-retardant means shall not be required.