What’s the Best Water Heater Temperature?
Water heating accounts for about 18 percent of your utility bills, so reducing the water heater temperature can lead to significant savings. Use this guide to help you determine the best water heater temperature for your situation.
Determining the Right Temperature
The standard temperature for a storage water heater is 140 degrees, but the US Department of Energy recommends lowering it to 120 degrees. This slows mineral buildup, reduces scalding at the tap and saves 4 to 22 percent on your annual water heating costs.
Be aware that setting your water heater lower than 120 degrees increases the risk of legionellae bacteria growth in the tank. Therefore, 120 degrees is as low as you should go on a daily basis. Still, you can lower the water heater temperature temporarily to save energy while you’re out of town for a few days.
Factors that Affect the Best Water Heater Temperature
The ideal temperature setting could be different for you compared to your neighbor. Here are the variables that affect how you should set your water heater:
- Dishwasher features: Most modern dishwashers come with a booster heater to help the appliance work more effectively. However, if you have an older dishwasher, you may need to keep your water heater at 140 degrees to ensure your dishes come clean.
- Health problems: The risk of bacterial growth in your water heater increases the lower you set the temperature. If you have a compromised immune system, you should consider keeping the temperature at 140 degrees.
- Number of people in your home: A higher water heater temperature means you have more hot water to go around. If only one or two people live in your home, 120-degree water should be just fine. However, the extra 20 degrees could be useful if you have a family of six or more.
- Children or older adults in your home: Lowering the temperature to 120 degrees can keep younger or older family members safe from scalding at the tap.
How to Adjust the Water Heater Temperature
If you want to set your water heater to a different temperature, follow these tips to make an accurate adjustment:
- Find the current temperature: Many water heater knobs lack temperature readouts. This means you’ll need to measure the temperature yourself. Run the hot water at full blast and place a thermometer under the stream to find out the current temperature.
- Check and adjust the thermostat dial: Mark the starting temperature on the dial with a marker, and then twist the knob slightly.
- Measure the temperature again: Wait a couple of hours, and then measure the water temperature with a thermometer again. If it still isn’t quite right, adjust the dial and re-measure the hot water until you’re satisfied.
- Mark the knob: Mark the new preferred setting on the temperature knob so you can make future adjustments easily.