Lower the temperature on your water heater. You’ll still have hot water, but the heater will use less energy. Blanket your water heater, especially on the top. But even better than a conventional water heater consider getting a tankless water heater.
Tankless water heaters also called instantaneous, continuous flow, inline, flash, on-demand or instant-on water heaters, instantly heat water as it flows through the device, and do not retain any water internally except for what is in the heat exchanger coil. They are more efficient and can save up to 60% of the energy used in standard heaters because they eliminate the need to reheat the water in conventional water heater tanks.
When installed where they are used they also eliminate heat loss in the pipes.