The Noritz FADM001 outdoor temperature sensor is a critical component for optimizing the performance of Noritz tankless water heaters. This sensor accurately measures outdoor temperatures, allowing the water heater to adjust its operation for maximum efficiency. Designed for easy installation, it enhances the system's ability to provide consistent hot water regardless of external conditions. The FADM001 is compatible with various Noritz models, making it an essential accessory for homeowners looking to improve energy efficiency and performance in their water heating systems.