The Rheem models were originally manufactured by Titan Tankless using Titan’s older style technology. Titan built these models for years with great reviews as they were built on the Titan platform. It appears Rheem bought Ecosmart tankless which now appears to be manufacturing their units. The Ecosmart uses similar technology to the Titan but is manufactured in China so the Rheem units now share those parts which is always a concern. We much preferred when Titan did the manufacturing in the USA but still feel the newer models are decent and get good reviews. A good company that has been around for many years that has made a mark for itself in the tankless industry.