Bosch Thermotechnology North America’s Therm C 1050 ES condensing tankless water heater has an efficiency increase of 2%, increasing its total energy factor to 0.94 overall. It also meets the new, stricter, low-NOx requirement passed by utility regulatory agencies in California and Vermont. Therm units from Bosch are designed with a wide flame pattern and secondary dilution air that results in a lower flame temperature during the heating