Energy Savings Swimming pools can be big energy hogs. In fact, the energy costs to heat the nation's 5.7 million pools and spas run in the billions of dollars annually. Outdoor pools use high amounts of energy to heat water, which loses heat during the evening and through evaporation.
Indoor pools use a lot of energy for systems that remove evaporation-caused humidity.
The following tips can help you save energy and money by reducing heat loss and evaporation in swimming pools. Use a pool cover. In both indoor and outdoor pools, nearly 7 percent of the heat is lost through evaporation. It also saves on refill water and chemicals. A pool covered just half the time can save up to 50 percent in annual energy costs.