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These "solar blankets" minimize water evaporation, just like a regular pool cover. As it insulates the surface of the pool, solar blankets also allow some of the sun's energy to go through the cover and into the water, where it turns into heat. This makes your pool water warmer, which means the swimming pool heater is required to run far less often and for shorter periods of time. Solar pool covers are one of the most effective and energy efficient ways to heat your pool.  Solar pool covers can extend your swimming season and reduce the amount of water that needs to be added by 30 to 50 percent. They can also reduce the amount of chemicals a pool needs by 35 to 60 percent, and help keep dirt and debris out of the pool, which reduces cleaning time. Solar pool heating panels collect heat from the sun to warm pool water. Once installed, they have no operating cost, are very easy for a home owner to install and are typically very durable in all climates. The only drawback is that if the sun doesn't shine, your pool isn't heated. Solar pool heating panels are an excellent solution for those who live in warmer climates and have a lot of sunny days throughout the year. These systems are in the same general price range as gas and heat pump heaters. Solar heating systems have minimal operating costs and they are the most cost-efficient choice for people who live in warm, sunny climates. These systems include 4 main features – a solar collector, a filter, a pump and a flow control valve.  The pump sends water through the filter and then through the solar collector, which heats the water and returns it back to the pool. If you live in a hot climate, the solar collector can help you cool your pool water down during the summer months. It does this by running the water through the solar collector during the night.

Summary:
Use a solar pool cover. Install solar pool heating panels. Invest in a solar heating system.