A. O. Smith Signature 100 Water Heater vs Noritz NRCB Combi Boiler

The A. O. Smith Signature 100 Water Heater is a residential tank water heater designed to provide reliable and efficient hot water for households. With a 6-year limited warranty, this water heater offers peace of mind and long-lasting performance.

The NRCB series is Noritz's combination boiler, which handles both space heating and domestic hot water from a single wall-mounted appliance. That combination is the point: instead of a boiler for the radiators and a separate tank water heater, one unit does both, freeing the floor space a tank would occupy and removing the standby heat loss that comes with keeping a tank hot around the clock. Because it is tankless on the hot water side, supply is continuous rather than limited by tank capacity, so back-to-back showers do not run out. Noritz is a tankless water heating specialist with residential and commercial ranges, and supports the NRCB with a sizing guide, plumbing diagrams, BIM and Revit files, installer training, a PROCard programme and installer and servicer locators.

• Reliable performance
• Long-lasting with 6-year warranty
• Easy to install and maintain
• Energy efficient design

• Replaces two appliances with one wall-mounted unit
• Continuous hot water with no tank to run out
• Frees the floor space a tank would take
• Strong installer documentation and training infrastructure

• May not be suitable for large households
• Not a tankless water heater option
• May require additional installation costs

• Requires professional installation and correct sizing
• Pricing runs through installers rather than being published
• Combi units can struggle with simultaneous heavy hot water draws