A backyard pool is a great addition during the hottest months of the summer, but what if you want to extend your swimming season? To do that, you will need to find a way to heat your pool water, but an electric heating pump can be expensive to install and run. For those living in sunny states, another option for heating the water is a system that runs on the sun's energy. Solar heated pools have become a popular way to maintain a comfortable temperature in the pool and extend the swimming season by many months.