If you consume a normal amount of water in your Sacrament home then most likely you are between 30 - 50 gallons a day. The overall energy cost of having tankless water heater can vary from home to home. If you are using this normal amount of water the you are going to be 24%–34% more energy efficient than a tank water heater.  If you are consuming larger amounts of hot water in your Sacramento home then you will be around 10 -  15% more energy efficient than a tank water heater. If you are really looking to be more energy efficient than a tank water heater then you can install a tankless water heater at every hot water outlet, this will put you around 27%–50% more efficient.