Tankless water heaters are designed to provide hot water on demand, and they require regular maintenance to operate efficiently and safely. Annual flushing is an essential part of this maintenance process, and failure to flush your tankless water heater annually can lead to a range of problems, including:

• Reduced efficiency: Over time, sediment, mineral deposits, and other debris can build up inside your tankless water heater. This buildup can reduce the efficiency of your unit and cause it to work harder to heat water, resulting in higher energy bills.

• Shortened lifespan: Sediment buildup can also cause your tankless water heater to wear out more quickly, shortening its lifespan and potentially leading to costly repairs or replacement.

• Reduced water flow: Sediment and debris can clog your unit's pipes and reduce water flow, making it harder to get hot water when you need it.

• Safety concerns: If sediment and debris buildup inside your tankless water heater, it can cause the unit to overheat, potentially leading to a fire or other safety hazards.

• Warranty issues: Many manufacturers require annual flushing as part of their warranty terms. Failure to follow these terms could void your warranty, leaving you responsible for any repairs or replacements.

In summary, annual flushing is a critical part of maintaining your tankless water heater's efficiency, lifespan, and safety. Be sure to follow your manufacturer's guidelines for maintenance and hire a qualified professional to perform any necessary maintenance or repairs.