When it comes to water temperature, a lot of us are like Goldilocks: We don't want it too hot or too cold, but just right. What you might not realize is that there are real ramifications for having the wrong temperature for your water heater.
A water heater that isn't properly managed can lead to out-of-control utility bills and potential health risks. According to the US Department of Energy, keeping your water temperature too high can create a risk of scalding -- and you might shocked to learn that studies have found tap water scald burns result in more than 1,500 hospital admissions and 100 deaths per year in the US. On top of that, adjusting your water heater temperature can save on your energy bill.
So how to do you adjust your water heater, and just what should you adjust it to? Don't worry. We'll help you get everything just right.
The correct temperature range
What exactly is the ideal water heater temperature? It can be found right at the intersection of safety, health and efficiency.
Most modern water heaters have a manufacturer-preset for water temperature set at 140 degrees Fahrenheit. That's fine, but it's also higher than recommended by the Department of Energy and the Consumer Product Safety Commission. Those agencies suggest you turn the water temperature down to about 120 F, noting that the difference in the risk of getting burned drops significantly with that little tweak. According to the American Burn Association, it takes just five seconds to get a severe burn from water set at 140 F. By contrast, it takes up to five minutes to get such a burn at 120 F.
If you want things to run a little hot, you can take extra safety precautions. "To address these risks, anti-scald devices can be installed on faucets," said Max Veggeberg, CEO of Tetra, a home services company.
There are risks to turning your water heater temperature down too low, too. While lowering temperatures reduces scalding risks, setting your water heater below 120 F may create concerns about bacterial growth, particularly Legionella, which can cause Legionnaires' disease. The Centers for Disease Control and Prevention notes that Legionella bacteria multiply in water temperatures between 77 and 113 F, making the 120 F recommendation a careful balance between safety and sanitization.
As for efficiency, water temperature matters quite a bit -- water heating costs typically account for nearly 20% of the average home’s energy bill, making it the second-largest energy expense for most people.
"The temperature setting directly affects how much energy your water heater consumes. The higher the temperature, the more energy it needs to maintain that temperature level," said David Miloshev, an HVAC expert at Fantastic Services. "Consequently, by setting the temperature correctly, you can effectively lower your energy consumption and reduce your energy bills."
Each 10-degree reduction in water temperature can save 3 to 5% on water heating costs. For the average American household, lowering a water heater from 140 to 120 F could translate to annual savings of between $36 and $61, per the Department of Energy. Additionally, lower temperatures reduce energy consumption and wear and tear, potentially extending the lifespan of your water heater and reducing maintenance costs.
Adjusting water heater temperature
So how do you adjust your water heater temperature? That answer will depend on the type of water heater that you have. And if you’re in the market for a water heater, you’ll want to keep in mind some of the challenges and benefits each type presents.
"Which one is best for you to save money will depend on your unique living situation," said Miloshev. "However, what you’ll need to consider with water heaters is the fuel type, availability and cost, size, energy efficiency and costs."
Gas water heaters
For gas water heaters, look for the temperature dial on the gas valve near the bottom of the tank. In some cases, this dial typically doesn't show actual temperatures, just warm to hot settings. Adjust in the direction you’re trying to shift your water temperature, then check the water temperature with a thermometer after 24 hours to see what the temperature is. Since the controls can be a bit spotty, make small adjustments until you reach your preferred temperature.
temperature dial on a water heater's gas valve with a caution message about scalding
Taylor Martin/CNET
Electric water heaters
Electric water heaters usually have two thermostats -- one at the top and one at the bottom of the tank -- hidden behind access panels. Before adjusting, turn off the power to the water heater at your circuit breaker. Remove the access panels and any insulation to expose the thermostats. Use a flathead screwdriver to adjust both thermostats to the same temperature. Replace insulation and panels, restore power and wait 24 hours before testing.
Tankless water heaters
Tankless water heaters are usually the easiest to adjust. Most have either a digital display panel or a temperature control dial. Simply adjust to your desired temperature following the manufacturer's instructions. Many models allow precise temperature settings in small increments.
"Tankless water heaters offer precise control, reducing overheating risks," said Veggeberg, "while tank systems require periodic maintenance to optimize safety and performance."
electric hot water heater
Martin LaMonica/CNET
Connected water heaters
Smart water heaters can be controlled through smartphone apps or home automation systems. Open the app, locate your water heater settings, and adjust the temperature with a simple slider or digital input. Some smart models also allow you to create schedules for different temperature settings throughout the day, which can be handy to save on bills if you’re on a variable rate plan.
Other considerations
Miloshev said that larger households with more people might want to raise the water temperature slightly to deal with increased usage. Likewise, keep in mind your daily routines. “If you run multiple appliances simultaneously, such as the dishwasher, washing machine and shower, a slightly higher setting can prevent inconveniences, such as the water turning cold in the middle of using it,” he said.
You should also consider the weather conditions where you live. Be practical. When it gets cold, you’ll probably want your water to be a bit hotter to compensate. “You’ll still need to be cautious not to overheat it because this can still be a safety hazard and energy waste," said Miloshev.
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