WaiWela is a company committed to the development of energy conserving and environmentally sound products since 1977. Based in Denver, this US tankless water heating units manufacturer is renowned for its quality and highly efficient products. Offering four mini-sized models and four medium-sized indoor/outdoor heaters, WaiWela covers the average residential hot water needs with success. The mini units can be used as re-heaters of warm water that is stored inside insulated tanks, while the normal-sized gas units support a standalone provision of heat of up to 200000 BTU/H. WaiWela units are made in Japan, and they are marketed with a 12-year limited warranty.