Hello ArCHmembers who are proud licensees of ArCHspec™. ArCHspec™ has had both a conventional HWH (Hot Water Heater) specification and a multiple tankless HWH specification in Division 15p. The multiple tankless spec is section 15400-1212. The conventional HWH (but high efficiency) is 15400-1300. It is recommended that the 15400-1212 multiple tankless HWH (either gas or electric) NOT be used. Instead, it is suggested that the 15400-1300 high efficiency conventional electric HWH be used.
Why: the multiple tankless HWHs could result in your project needing many more amps and possibly even a higher MDP (Main Distribution Panel) and larger main disconnect and larger cables feeding the project. These increases in electrical power infrastructure are sure to offset any energy performance enhancements.
Therefore, it is suggested that the conventional HWH (but high-efficiency) henceforth be specified, rather than the multiple tankless approach.