Designed with "totally managed" water flow, Universal H-Series pool and spa heaters from Hayward® save energy and money by reducing pump run time. Their low NOx emissions meet air quality standards in all low-NOx areas, so you can rest easy knowing their environmental impact is low. Available in both Propane Gas and Natural Gas options. Extends the swim season, delivering 83% thermal efficiency powered by propane gas Designed for on-demand heat performance with fast heat up times Corrosion-resistant titanium heat exchanger works well with salt systems Compare Savings Designed with "totally managed" water flow, Universal H-Series heaters save energy (and money) by reducing pump run time. Universal H-Series heaters boast industry-leading hydraulic performance coupled with lightning-fast speed-to-heat capability. Compare savings with the Hayward Energy Calculator