If you have a house, you probably have some sort of hot water heater. But there’s no universal temperature for “hot” water—this is something you have to set yourself. So what’s the ideal hot water heater temperature? Here’s what you need to know.
For most homes, it’s 120 degrees Fahrenheit
Let’s get this out of the way first: there’s no “perfect” hot water heater temperature for every single house. Like most things, it depends on your household’s needs, including whether any children or elderly people are living with you, and whether anyone has a compromised immune system.
Having said that, if you don’t live with anyone who fits into the categories above, 120 degrees Fahrenheit is probably the best temperature setting for your hot water heater. The U.S. Department of Energy recommends the 120 degree-mark for both maintenance and savings purposes. Guidelines from the department explain that most hot water heaters are automatically set to 140 degrees Fahrenheit, but that’s usually unnecessary. Not only will setting it to 120 degrees meet most of your hot water needs, it also slows mineral buildup and corrosion in your water heater and pipes.
Their biggest argument, though—being the Department of Energy and all—is that setting your hot water heater to 120 degrees instead of 140 degrees can save you energy, and therefore money:
Savings resulting from turning down your water heater temperature are based on two components: reduced standby losses (heat lost from water heater into surrounding basement area); and consumption (from water demand or use in your home). Set too high, or at 140ºF, your water heater can waste anywhere from $36 to $61 annually in standby heat losses and more than $400 in demand losses.
Another argument for the 120-degree setting: if you have children or older people in your house, they are less likely to get scalded by water from the tap at this temperature.
But for others, 140 degrees Fahrenheit is best
The primary reason for keeping your hot water heater set at 140 degrees is if you have someone in your household with a suppressed immune system or chronic respiratory disease, according to the Department of Energy. Similarly, the U.S. Occupational Safety and Health Administration (OSHA) recommends the 140-degree setting for preventing Legionnaires’ disease. Additionally, if you have a dishwater that doesn’t pre-heat the water, you’re either going to want to set your hot water heater to 140 degrees.
How to check and adjust your hot water heater setting
If you’re not sure what temperature your hot water heater is set to, simply look at the dial. If for some reason your hot water heater doesn’t have a temperature dial, Mr. Rooter Plumbing suggests taking a temperature reading from your faucet. To do this, turn the hot water all the way up, allow it to run for a few minutes, and then take the water’s temperature.
Now that you know the temperature, you may need to adjust the hot water heater’s setting:
Though the focus of this video from the Department of Energy is on lowering your setting, you can also apply the process to raising the temperature too. Plus, it provides instructions for both electric and gas hot water heaters.
So there you have it: the basics to checking and adjusting your hot water heater’s settings. When in doubt—or if there are any additional issues—call in a professional. But if you’re doing a quick temp check, you should be fine on your own.
This story was originally published on 11/15/13 and was updated on 10/22/19 to provide more thorough and current information.