The solar collector is the part of the pool heater that water flows through to become heated

During the day the water flowing through this collector will be heated by the sun, if you happen to live in a hot climate, then circulating the water through the collector will actually cool the water down for you. Collectors for solar swimming pool heaters usually are made from heavy duty rubber or plastic that has had ultraviolet light inhibitor. Your collector might be glazed or unglazed. Glazing helps protect the panels if you will be using the pool in below freezing temperatures. Most glazed systems are more expensive than unglazed collectors.