On demand hot water - no delay - Cut energy waste - Flow switch activates heater only when water is running, no standby heat loss | 99% Efficient, .99 energy factor - Endless hot water - No storage capacity to deplete | Reduces installation cost and material - No T&P valve required (check local codes) | Thermo optical sensor and predictive control algorithm ensures optimal heat management | Easy Installation - Simple NPT fittings that require no soldering. Unit mounts directly to the wall with common hardware