Hawaii Boiler is a type of hot water heater that is used to provide hot water for homes and businesses. It is typically powered by natural gas or propane and is a cost-effective way to heat water for use in showers, laundry, dishwashing, and other activities. Hawaii Boiler is designed to be energy-efficient and environmentally friendly, using less water and energy than traditional hot water heaters. The two main types of Hawaii Boilers are tankless and tank-type. Tankless Hawaii Boilers provide hot water on demand and are more energy-efficient than tank-type models. Tank-type Hawaii Boilers store hot water in a tank and are more cost-effective than tankless models.