Water heater/pool heater is used for swimming pool, spa pool, etc.Electrical instant water heaters of swimming pool will keep pools heated at a consistent temperature between eighty and ninety degrees. If you are set in a daily, year-round swimming routine then this heater is the choice for you.Especially in cold days when you want to swim in the pool, water heater can heat the pool water in a certain temperature and provide you and your family a comfortable environment the whole seasons.