Although some manufacturers set water heater thermostats at 140ºF, most households usually only require them to be set at 120ºF, which also slows mineral buildup and corrosion in your water heater and pipes.
In the US, the maximum legal temperature for a water heater in a residential setting is 120 degrees. Most folks want to run at 125-130 degrees but be careful. The Federal law that stipulates the max temperature is because of folks, especially kids, getting burned by the water.
Though the DOE says you can save money on hot water by lowering the maximum temperature of your water heater from 140° F to 120° F, we don't necessarily recommend it. That's because the lower temperature might invite opportunistic bacteria—including Legionella, associated with Legionnaires' disease—to proliferate.
Manufacturers often recommend a hot water heater temperature between 120 to 140°F, and there's a reason for this. The Occupational Safety and Health Administration (OSHA) recommends a recommended hot water temperature of at least 122 degrees to prevent the growth of harmful bacteria.
If the temperature is above 65°C, then the water will be too hot to use, and it increases the risk of serious burns. Keeping the temperature at a safe level, 60°C to 65°C, makes the water hot enough to use and hot enough to kill unwanted bacteria.
Although some manufacturers set water heater thermostats at 140ºF, most households usually only require them to be set at 120ºF, which also slows mineral buildup and corrosion in your water heater and pipes.
Hot water needs to be stored above 60°C in hot water systems to prevent bacteria growth (such as Legionella), but a tempering valve ensures that the water comes out of the tap at a lower temperature.
Temperature Is Too High
The most obvious reason for a high water heater gas bill is if the temperature is set too high. According to experts, most homeowners should keep water heater temperatures between 120 and 140 degrees F.
According to most dermatologists, the ideal shower temperature is anywhere between 98°F (37°C) and 104°F (40°C)—and no more than 105 °F (41°C). Rinsing under lukewarm water allows you to stay comfortable and maintain your body temperature while reaping all the benefits of both hot and cold showers.
C - 150° F - About 1-1/2 seconds. B - 140° F - Less than 5 seconds. A - 130° F - About 30 seconds. HOT - 120° F - More than 5 minutes. LOW - 80° F - No hazard.
Turning your water heater off completely when it's not in use can help you save a small amount of money each month on your energy bills, but the hassle of manually turning your unit off and on typically outweighs the benefits.
We recommend always keeping the heater set between 110 and 120 degrees. In the summer, try setting your water heater temperature at the low end of this scale, placing it close to or at 110 degrees.
According to Centers for Disease Control and Prevention (CDC), water temperatures ranging from 130 to 140 degrees Fahrenheit(°F) can eliminate most of the harmful bacteria. However, be warned that these high temperatures can also increase the risk of scalding.
Water Heater Temperature Recommendations
120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting.
For most homes, a domestic hot water temperature around 45-50 °C during summer is more than sufficient. This ensures the water is adequately hot for daily needs without wasting energy through overheating. It is also a safety measure that prevents scalding, especially with children in the house.
Anything between 120 and 140 degrees is within the safe range, which means it really all comes down to a matter of personal preference. If you have younger children in the house, you are always better to have your water heater set to 120 degrees to prevent scalding.
The Standards state that hot water must be regulated at a particular temperature to reduce scalding – 60°C is the accepted temperature for stored water and 50°C for water flowing from an outlet.
The recommended temperature setting for a water heater is 120 degrees. This temperature is not only energy efficient, but it can also help extend the life of your water heater and reduce the risk of leaks or other malfunctions, saving you money!
Sediment can build up over time in a water heater, shortening its lifespan. To prevent this, you should flush your water heater at least once per year. Flushing will help to remove any sediment that has built up and improve the efficiency of your water heater.
Water heating is the second largest energy expense in your home, accounting for about 18% of your utility bill. To conserve hot water, you can fix leaks, install low-flow fixtures, insulate accessible hot water lines, and purchase an ENERGY STAR certified dishwasher and clothes washer.
The best temperature setting for a hot water heater is between 120 and 140 degrees. Below 120 degrees, bacteria can develop in the stagnant water sitting in the tank. Above 140 degrees, the water is so hot that you and your family members can be at risk for scalding in as little as two seconds.
If you opt to lower your water heater temperature, additional savings can come from the reduced energy required to heat the same amount of water to 120 degrees instead of 140 degrees. Experts also recommend turning down your water heater to its lowest settings if you plan to be away for an extended period.
You can easily save energy in the winter by setting the thermostat to around 68°F to 70°F while you're awake and setting it lower while you're asleep or away from home.