To adjust the thermostat on a water heater, you'll need to locate the thermostat (which varies by heater type), safely access it, and then set it to your desired temperature, typically around 120°F (49°C) for optimal balance of safety and efficiency.
Adjusting your water heater's temperature can help save energy, prevent scalding, and ensure you have enough hot water. The process differs slightly between electric and gas models.
Why Adjust Your Water Heater Temperature?
Setting the correct water heater temperature offers several benefits:
- Energy Savings: Lowering the temperature from 140°F to 120°F can reduce your water heating costs by 6%-10% annually.
- Safety: A temperature of 120°F significantly reduces the risk of scalding, especially for children and the elderly. Water at 140°F can cause third-degree burns in less than 5 seconds.
- Hot Water Supply: While a lower temperature saves energy, ensuring it's not too low will prevent running out of hot water for daily needs.
Safety First: Essential Precautions
Before attempting any adjustments, always prioritize safety:
- Turn Off Power (Electric Heaters): For electric water heaters, always turn off the power at the circuit breaker before opening any access panels. This prevents electrical shock.
- Turn Off Gas Supply (Gas Heaters): For gas water heaters, locate the gas shut-off valve on the gas line leading to the heater and turn it to the "OFF" position if you plan to do more than just turn the dial. For simple dial adjustment, this isn't strictly necessary, but be aware of the pilot light status.
- Wear Protective Gear: Gloves can protect your hands.
- Consult Your Manual: Always refer to your water heater's owner's manual for model-specific instructions and warnings.
Adjusting an Electric Water Heater Thermostat
Electric water heaters often have two thermostats, one for the upper heating element and one for the lower, typically located behind access panels. Both should be set to the same temperature.
Step-by-Step Guide for Electric Water Heaters:
- Cut the Power: Go to your home's main electrical panel and turn off the circuit breaker labeled for your water heater. If it's not clearly labeled, turn off the main breaker to the house for maximum safety.
- Locate Access Panels: Most electric water heaters have two removable access panels (usually rectangular or circular) on the side, one near the top and one near the bottom.
- Remove Access Panels: Using a Phillips screwdriver, remove the screws securing the upper access panel. Repeat for the lower panel if necessary, although sometimes only one thermostat needs adjusting, or they both adjust simultaneously depending on the model.
- Remove Insulation: Behind each panel, you'll typically find a styrofoam insulator or fiberglass insulation. Carefully pull this off to expose the thermostat.
- Identify the Thermostat: The thermostat is usually a small dial or lever with temperature markings (e.g., "Hot," "Warm," "A," "B," "C," or actual temperature degrees). There may also be a red reset button nearby.
- Adjust the Temperature:
- Use a flat-head screwdriver or your fingers (depending on the dial type) to turn the thermostat to your desired setting.
- The recommended setting for most households is 120°F (49°C).
- If there are two thermostats, ensure both are set to the same temperature to ensure efficient operation.
- Replace Components: Once adjusted, replace the styrofoam insulator, reattach the access panel with its screws, and then repeat for the lower thermostat if adjusted.
- Restore Power: Go back to your electrical panel and turn the water heater's circuit breaker back on.
- Test the Temperature: After about an hour, run the hot water at a faucet and use a thermometer to check the temperature. Adjust further if needed.
Adjusting a Gas Water Heater Thermostat
Gas water heaters typically have a single thermostat control dial located on the front of the gas valve, usually near the bottom of the tank.
Step-by-Step Guide for Gas Water Heaters:
- Locate the Thermostat Dial: The thermostat is usually a large, prominent dial on the gas control valve, often found near the bottom of the water heater.
- Identify Settings: The dial will have markings such as:
- "Warm," "Hot," "Very Hot"
- Specific temperatures (e.g., 120°F, 130°F, 140°F)
- Letters (e.g., "A," "B," "C," where "A" might be 120°F)
- "Vacation" or "Pilot" (a very low setting to maintain the pilot light without heating the water much).
- Adjust the Temperature: Simply turn the dial to your desired setting. For most households, 120°F (49°C) is recommended. Many manufacturers label 120°F as a safe and efficient setting.
- Monitor and Test: Allow at least an hour for the water heater to adjust to the new setting. Then, run hot water at a faucet and use a thermometer to verify the temperature.
Recommended Water Heater Temperatures
| Purpose | Recommended Temperature | Notes |
|---|---|---|
| General Household Use | 120°F (49°C) | Balances safety, energy efficiency, and sufficient hot water for most needs. |
| Increased Demand | 130-140°F (54-60°C) | For large families, long showers, or dishwashers without booster heaters. Consider a mixing valve for safety. |
| Sanitization | 140°F (60°C) | Often used for dishwashers with no internal heating element. Not recommended for direct household use without a mixing valve. |
| Vacation Mode | "Vacation" or lowest | Maintains pilot light on gas heaters without heating water, saving energy while you're away. |
Source: Energy.gov
Troubleshooting Common Issues
- No Hot Water After Adjustment: Double-check that the power is on (electric) or the gas is on and pilot is lit (gas). Ensure thermostats are set correctly.
- Water Too Hot/Cold: Give the heater enough time (at least an hour) to respond to adjustments. If still off, adjust slightly and retest.
- Reset Button Tripped (Electric): If you have no hot water, check for a red reset button near the thermostat. Press it firmly. If it keeps tripping, there might be an underlying issue requiring professional help.
By following these steps, you can safely and effectively adjust your water heater's thermostat to meet your household's needs.
