Where water quality plays a significant role in a water heater’s performance and cost of operation, A. O. Smith’s Product Preservers Tankless Anti-Scale System prevents hard water scale from accumulating. Scale can reduce efficiency, cause the heat exchanger to overheat, and eventually damage a water heater to the point it begins to leak water. The unit is designed to promote the formation of inactive scale crystals, which flow through the water heater without sticking to the heat exchanger. The filter does not add chemicals to the water or require electricity. The system is virtually maintenance-free, requiring only a simple filter change every two years, and does not need to be flushed with a cleaning solution to remove scale buildup. 800-527-1953; www.hotwater.com.