Thermal covers are the first step to heating your pool naturally using solar energy. You do not need to install a heat pump or solar panels. Thermal covers increases water temperature by 6-8oc and it also retains heat overnight and from heating systems. It saves water as it reduce evaporation by 98%+ and the water is always kept clean. Manapools thermal covers are made from 400 micron polyethylene with UV inhibitors that makes that to withstand local climate conditions and by covering your pool with Manapools Thermal Covers, you can extend your autumn and spring swimming season by 6 weeks. Depending on how you take care of your Thermal Covers, it will last you 6 good years before installing a new one.