Adjusting your water heater temperature is a simple yet effective way to save energy in your home. The right temperature setting ensures you have enough hot water for daily tasks while preventing scalding and reducing energy waste. In this guide, we’ll explore how to adjust the temperature on different types of water heaters and discuss the ideal temperature setting for most households. Richard Trethewey, the plumbing and heating expert from This Old House, demonstrates the process for various water heater types in the video above.
Understanding Water Heater Temperature Settings
Before adjusting your water heater, it’s important to understand the ideal temperature setting and why it matters. The recommended temperature for most households strikes a balance between safety, energy efficiency, and practical use.
Ideal Temperature Setting
The U.S. Department of Energy recommends setting your water heater to 120°F (49°C) for most households. This temperature is high enough to meet daily needs while minimizing safety risks and energy waste. Ensuring that your water heater is set to this temperature can also prolong the lifespan of your unit, reducing the need for premature replacements or repairs.
Safety Considerations
Water temperatures above 120°F can pose a scalding risk, especially for children and the elderly. In fact, water at 140°F can cause third-degree burns in just five seconds. Plumbing codes typically require that water from shower heads not exceed 115°F to prevent scalding injuries. It’s essential to check the temperature at all outlets to ensure consistency and avoid any dangerous surprises.
Energy Efficiency
Higher temperature settings lead to greater energy consumption. For every 10°F reduction in water temperature, you can save 3–5% on your water heating costs. Keeping your water heater at a lower temperature also reduces standby heat loss from the tank, which occurs as heat escapes from the unit into the surrounding area. Many older homes with less insulation can greatly benefit from this practice.
How To Adjust Different Types of Water Heaters
The process for adjusting water heater temperature varies depending on the type of unit you have. Here’s how to adjust the most common types of water heaters:
Gas Tank Water Heaters
Gas tank water heaters are common in many households. Their temperature adjustment process is straightforward:
- Locate the temperature dial on the gas control valve near the bottom of the tank.
- Use a flathead screwdriver to adjust the dial to your desired temperature.
- Wait at least three hours before checking the water temperature at a faucet.
- If necessary, readjust the dial and wait another few hours.
Electric Tank Water Heaters
Electric tank water heaters require a bit more precaution due to the involvement of electricity:
- Turn off the power to the water heater at the circuit breaker.
- Remove the access panel(s) to reveal the thermostat(s).
- Adjust the temperature using a flathead screwdriver.
- Replace the access panel(s) and restore power.
- Wait at least three hours before testing the water temperature.
- For dual-element heaters, ensure both thermostats are set to the same temperature.
Tankless Water Heaters
Tankless water heaters, often referred to as on-demand units, have a different adjustment mechanism:
- Locate the temperature control panel on the unit.
- Use the digital display or buttons to adjust the temperature setting.
- Wait a few minutes for the change to take effect before testing.
- Make fine adjustments as necessary to achieve the desired temperature.
Testing Water Temperature
After adjusting your water heater, test the water temperature to ensure it’s at the desired level. Here’s how to do it:
- Let the hot water run at the faucet furthest from the water heater for at least three minutes.
- Fill a glass with hot water.
- Use a cooking thermometer to measure the water temperature.
- If the temperature isn’t at your desired setting, readjust the water heater and test again after a few hours.
- Repeat this process at different faucets to ensure consistency throughout your home.
Special Considerations for Water Heater Temperature
While 120°F is the recommended setting for most households, there are some situations where you might need to adjust this temperature. These special considerations can help you determine the best settings for your unique needs.
Dishwashers and Water Temperature
Many people worry that 120°F isn’t hot enough for their dishwasher to sanitize dishes effectively. However, most modern dishwashers have built-in heating elements that can boost water temperature as needed. If your dishwasher doesn’t have this feature, you may need to set your water heater slightly higher. Always check your dishwasher’s manual for the optimal water temperature setting to ensure proper function.
Elderly or Immunocompromised Individuals
Households with elderly or immunocompromised individuals may need to set their water heater to 140°F to reduce the risk of Legionella bacteria growth. However, it’s necessary to install anti-scald devices on faucets and showerheads to prevent burns at this higher temperature. Regular checks and maintenance can help in balancing needs for safety and health.
Vacation Settings
If you’re going away for an extended period, consider lowering your water heater temperature to its vacation setting (usually around 50°F) to save energy. Just remember to raise it back to its normal setting when you return. Remembering to adjust the temperature back can help avoid surprises when hot water is temporarily unavailable.
Newborns and Young Children
Extra caution is necessary in households with newborns or young children. Maintaining your water heater at 120°F or below prevents accidental scalding during bath time or handwashing. Additionally, consider placing child-safe locks on faucets to manage water accessibility.
Troubleshooting Common Water Heater Temperature Issues
Sometimes, adjusting your water heater doesn’t solve temperature-related problems. Here are some common issues and how to address them:
Not Enough Hot Water
If you’re not getting enough hot water, check these potential causes:
- Sediment buildup in the tank: Flush your water heater regularly to remove sediment
- Faulty heating element (in electric water heaters): A professional can replace heating elements if needed
- Malfunctioning thermostat: Replace if it’s not reading or setting temperatures correctly
- Undersized water heater for your household needs: Consider upgrading to a larger unit to meet your demands
Inconsistent Water Temperature
If your water temperature fluctuates, consider these possible reasons:
- Crossed hot and cold water lines: Ensure your plumbing is correctly installed
- Faulty tempering valve in your shower: Repair or replace as needed
- Malfunctioning thermostat: Sometimes a simple readjustment or replacement can correct this
- Distance from the water heater to the faucet: Insulating your pipes can help maintain a consistent temperature
Water Too Hot Despite Lower Settings
If your water is too hot even after lowering the temperature, you might have:
- A stuck thermostat: A stuck thermostat needs immediate replacement by a professional
- Improper thermostat calibration: Recalibration can be handled during routine maintenance
- A faulty temperature-pressure relief valve: Have this checked and replaced if necessary to prevent potential hazards
Corrosion and Rust
Corrosion and rust in the tank can affect temperature regulation. To prolong its life and ensure proper function, regularly inspect and maintain your water heater, including checking the anode rod.
Energy-Saving Tips for Water Heaters
Adjusting your water heater temperature is just one way to save energy. In addition, you can reduce your water heating costs by insulating your water heater tank and hot water pipes. This helps retain heat and reduces energy consumption. Fix leaky faucets promptly, as even a small drip can lead to significant water and energy waste. Similarly, consider installing low-flow showerheads and faucet aerators—these devices reduce water usage without compromising performance.
Use cold water for laundry when possible. Many fabrics clean well with cold water, saving on heating costs. Finally, schedule regular maintenance for your water heater. This will ensure it operates efficiently and catch minor issues before they become significant problems.
Our Conclusion
Adjusting your water heater temperature is a simple yet effective way to enhance safety and energy efficiency in your home. By setting the temperature to 120°F, you can prevent scalding risks, reduce energy consumption, and still meet your household’s hot water needs. Remember to test the water temperature after making adjustments and consider your specific household requirements when choosing the ideal setting. Regular maintenance and attention to special considerations can further ensure that your water heating system operates safely and efficiently.
