The TOU Setup app allows you to get a Time of Use (TOU) rate from a California utility and import it into your water heater so it minimizes being on at expensive times. The water heater will pre-heat itself right before the expensive time of day, and then try to avoid coming on during the expensive time of the day, unless it determines that it needs to add just a bit of hot water to avoid delivering water that is at a lower than expected temperature.