Profile: Island Hot Tub deals with traditional soaking tubs. Our product line includes wood fired water heater, propane water heater, accessories and connection kit. Our Chofu model is a precision built wood-burning water heater designed specifically for hot tubs. The stove body of the Chofu is made with high quality stainless steel, grade (316). It circulates water using the principal of thermosiphon (the pumping action created by rising hot water), eliminating the need for a circulating pump or electricity. Our chofu propane water heater is a water heater designed specifically for hot tubs. The propane water heater is designed for outdoor use, with a durable powder coated steel outer casing and a stainless steel exhaust cowling.