The Hayward Universal H-Series gas heater is one of the most energy-efficient Pool and Spa heating solutions on the market! Its ground-breaking hydraulic design reduces pump circulation run time, giving you an energy savings of up to 18%! This unit is perfect for the environmentally conscious Pool and Spa owner thanks to its Low NOx capabilities. The Hayward Universal H-Series gas heater meets or exceeds the South Coast Air Quality Management District's (SCAQMD) Low NOx emission standards, making it ideal for use in states with strict air quality guidelines such as California. All Hayward heat exchangers are manufactured with highly resilient Cupro-Nickel, which increases the unit's durability and longevity, even under the harshest conditions. The durable, energy-efficient, and environmentally friendly Universal H-Series gas heater is an excellent, guilt-free solution for all of your pool and spa heating needs.