Standard 40 gallon hot-water heaters work like this: they always stay filled with water; they heat the water to the desired temperature; and then they keep it perpetually at that temperature. Manufacturers sometimes set hot water temperatures higher than they need to be—even to the point of making dangerously scalding water. You can easily take matters into your own hands by turning the knob to a lower temperature.
Tips & Tricks
Consult your water heater owner’s manual for instructions. Generally, the process of adjusting the temperature is straightforward. Simply look for the thermostat dial near the bottom of the tank and turn it to the appropriate temperature.
See how low you can go. Try setting your water heater as low as 115 degrees F or lower until you find the tipping point at which it is no longer hot enough. Then you’ll know you’re saving as much energy and money as possible.
Give your water heater a blanket. By blanketing your water heater with insulating material, you can further reduce your utility bill. It is also important to insulate any pipes that carry hot water; look for the copper pipes connected to the hot water heater.
Give your water heater a vacation. If you will be away from home for 3 days or more, turn your water heater down to the lowest setting or off altogether until you return.
Switch to on-demand heating. On demand, tankless water heaters do not store large batches of hot water, but rather heat the water electrically as you need it. By eliminating the need to maintain hot water at all times, the tankless systems reduce wasted energy.
Web & Print Resources
Water heater temperature information:
Water heater insulation:
For each 10°F reduction in water temperature, you can save between 3–5% in energy costs. Source