Natural gas pool heaters and propane heaters are the most popular type of pool heater, as they are made to heat the water quickly and maintain your desired temperature—no matter the weather. If you choose to buy a natural gas pool heater, keep in mind the fuel prices and availability in your area. Today, many natural gas pool heaters are available in low-nitrogen oxide models (low NOx), which means they are designed to produce fewer emissions than traditional gas heaters. Natural gas pool heaters are a great choice for an environmentally conscious swimming pool owner. The natural gas models are from top-rated brands. The Hayward H-Series heater is a leader in energy efficiency. Its design is able to heat an 800 gallon pool by 30 degrees in less than an hour. It’s also equipped with a digital LED control panel, so you can easily control and maintain the exact water temperature. The Pentair MasterTemp is compact, and features hot surface ignition and digital controls for easy operation. Its rustproof exterior and quiet operation are standard features in each MasterTemp.