How to Adjust the Temperature on a Water Heater: A Comprehensive Guide

Learning how to adjust the temperature on a water heater is a vital task for maintaining household safety, energy efficiency, and the longevity of your appliance. This step-by-step guide is designed to help you understand the process of regulating the temperature on water heaters with storage tanks, whether they are powered by gas or electricity.

Proper temperature control protects you and your family from risks such as scalding burns while also preventing issues like heating element failure. By following the instructions provided, you can ensure your water heater operates at its optimal performance level.

Why Temperature Adjustment is Important

Understanding how to adjust the temperature on a water heater is crucial for several reasons.

One of the primary reasons for the proper temperature selection is to prevent scalding burns, especially for vulnerable groups like children and seniors. Statistics from the American Burn Association (opens in pdf) reveal that approximately 21,000 children are injured each year due to excessively hot water from taps. This underscores the need to carefully regulate the thermostat settings.

Another significant benefit of adjusting the temperature is reducing energy consumption and lowering utility bills. A small correction, such as lowering the temperature by 10°F, can lead to energy savings of around 3% to 5%.

Conversely, maintaining an excessively low temperature could deplete the hot water supply quickly or even allow harmful bacteria, such as Legionella, to grow within the tank.

Safe Temperature Settings for Water Heaters

Most residential water heaters are designed to produce water temperatures between 80°F and 160°F, with some commercial models capable of reaching even higher levels. However, manufacturers typically set the default temperature to a safe range of 120°F to 125°F. This setting balances safety and efficiency while meeting most household needs.

Different applications may require different temperature levels.

For example, a shower or bath generally works well at 120°F, while tasks like dishwashing or laundry may benefit from temperatures closer to 140°F.

However, the risks of burns increase significantly as the water temperature rises:

• At 120°F, it takes over 5 minutes to cause a burn.
• At 125°F, burns occur in about 2 minutes.
• At 130°F, burns happen in 30 seconds.
• At 140°F, the risk is immediate, with burns occurring in less than 5 seconds.

For homes with children, elderly individuals, or anyone with sensitive skin, it’s advisable to keep the temperature closer to 120°F. Alternatively, installing anti-scald devices, such as mixing valves, can help ensure safer water temperatures at points of use by blending hot and cold water.

The Dangers of Improper Temperature Adjustment

An improperly adjusted thermostat can lead to various problems. If the water is excessively hot despite attempts to lower the temperature, the thermostat may be faulty. In electric water heaters, this could also involve the failure of the reset button, which is designed to shut off power to the heating element if overheating occurs.

Signs of overheating include:

• Steam emitting from the tank’s Temperature and Pressure Relief (TPR) valve.
• Boiling sounds coming from the tank.
• Water dripping or flowing from the TPR valve as a safety mechanism.

Another common issue is sediment buildup on the heating elements, leading to inefficiency, corrosion, or even burnout.

Regular maintenance, such as flushing the tank, is essential to prevent these problems.

How to Adjust the Temperature on an Electric Water Heater

To adjust the temperature on an electric water heater:

1. Start by measuring the current water temperature at a tap. The goal is to achieve a consistent 120°F.
2. Turn off the power supply to the water heater at the circuit breaker to ensure safety.
3. Locate the access panels on the heater, typically covering both the upper and lower thermostats. Remove these panels along with any insulation.
4. Use a flathead screwdriver to turn the adjustment dial to the desired temperature.
5. Replace the insulation and access panels, then restore power to the unit.
6. Allow a few hours for the water to heat to the new temperature, then recheck the tap water temperature. Mark the thermostat setting for future reference if the temperature is satisfactory.

How to Adjust the Temperature on a Gas Water Heater

Adjusting the temperature on a gas water heater is typically more straightforward:

1. Locate the thermostat, which is part of the gas control valve near the base of the tank.
2. Most thermostats feature a dial that can be turned to increase or decrease the temperature. For example, on White Rodgers valves, turn the dial counterclockwise to increase the heat. For Honeywell and Robertshaw valves, turn it clockwise.
3. Refer to the temperature markings on the dial, often labeled as “Warm” (120°F), “Hot” (160°F), or “Vacation” mode (around 85°F).
4. Adjust the dial to the desired setting and monitor the results after a few hours.

Balancing Safety, Comfort, and Efficiency

Maintaining the right water heater temperature requires striking a balance between comfort and efficiency. Knowing how to adjust the temperature on a water heater and following expert advice, such as the U.S. Environmental Protection Agency’s recommendation of 120°F, ensures safety while preventing bacteria growth and keeping energy costs manageable.

In addition to adjusting the temperature, regular maintenance—such as flushing out sediment, checking the TPR valve, and monitoring thermostat performance—is essential for the long-term reliability of your water heater.

By taking these steps, you can enjoy a consistent supply of hot water that meets your household needs while prioritizing safety and conserving energy.