Choosing the right temperature setting for your water heater comes down to finding the right balance of safety, efficiency and practicality. In general, water temperatures above 120°F are not necessary for many household tasks. Laundry, dishwashing, and bathing can all be effectively accomplished at or below this temperature, making higher settings wasteful.
While it might seem like a good idea to always have very hot water available, the potential risks and costs usually outweigh the benefits.
Optimal Water Heater Temperature Setting for Safety and Efficiency
We recommend setting it at 120°F (49°C) or lower. Why this temperature? Let’s break it down:
Safety First: Preventing Scalding
Water temperatures above 120°F can cause severe burns, especially for children and the elderly who are more vulnerable and may accidentally turn on the hot water. By keeping the temperature at or below this level, the risk of scalds is significantly reduced.
According to the U.S. Consumer Product Safety Commission, water at 140°F can burn skin in six seconds, and most tap water scald injuries happen to older adults and children under five. The CPSC recommends setting water heaters to 120°F.
Installing an anti-scald device to prevent excessive hot water is essential in households with vulnerable residents such as young children or elderly adults.
Energy Efficiency For Lower Costs
Some manufacturers ship water heaters set to 140°F, but the 120°F setting the CPSC recommends is enough for most households. The lower setting wastes less energy keeping stored water hot, and it slows mineral buildup and corrosion in the water heater and pipes.
Extending the Lifespan of the Water Heater
Another often overlooked disadvantage of setting the water heater temperature too high is that it can accelerate wear and tear. The elements in electric water heaters and the burners in gas models can degrade faster under higher temperatures, leading to more frequent repairs and earlier replacement.
Setting the water heater thermostat to 120°F or lower strikes a good balance between providing hot enough water for household needs and keeping energy costs down.
Preventing Over-Pressure
Water heaters are designed to handle specific pressure levels. Excessively high temperatures can raise the water pressure beyond these levels, potentially leading to leaks or even a rupture. This is why water heaters have temperature and pressure relief valves, but consistently high temperatures can put undue stress on these safety features.
Is 120°F Hot Enough to Control Legionella?
Legionella bacteria grow best between 77°F and 113°F. For large buildings, the CDC recommends storing hot water above 140°F, keeping circulating hot water at 120°F or above, and installing thermostatic mixing valves near fixtures to prevent scalding. For most homes, 120°F is the recommended setting. If someone in your home has a weakened immune system, ask a plumber about storing water at 140°F with a mixing valve that delivers safer water at the tap.
How to Adjust Your Water Heater Temperature
Most water heaters have a dial or digital pad near the bottom of the tank to adjust the temperature. Be sure to read the manufacturer’s instruction to ensure safe operation. After adjusting the temperature run hot water at a faucet for at least a minute, then use a thermometer to check the water temperature. The temperature may not match the set temperature precisely, but it’s important to check that it is not overheating the water.
Additional Tips for Water Heater Efficiency
Regular Maintenance
Ensure regular maintenance of your water heater. Annual flushing of the tank will prevent sediment build-up that can affect temperature settings and efficiency. The plumbers at Central Heating Cooling Plumbing Electrical can help maintain your water heater to ensure it is running safely and efficiently.
Insulation
Consider insulating older water heater tanks and pipes to improve efficiency. Use insulation specifically designed for water heater tanks.
Upgrade
If your water heater is old, consider upgrading to a more energy-efficient model. The cost saving in lower energy bills can make it a wise investment.
Water Heater Temperature FAQ
What temperature should a water heater be set to?
120°F for most homes. The U.S. Consumer Product Safety Commission recommends it.
Is 140°F too hot for a water heater?
For water at the tap, yes. Water at 140°F can cause a burn in six seconds. Homes that store water at 140°F for health reasons should use a thermostatic mixing valve.
How do I check my water heater’s temperature?
Run hot water at a faucet for at least a minute, then measure it with a thermometer.
Setting your water heater to the right temperature is important for safety, efficiency and maximizing the lifespan of the unit. Have questions about your home’s water heater? At Central Heating Cooling Plumbing Electrical in Kalispell, we are always here to help with your plumbing needs. Don’t hesitate to contact us for any water heater or plumbing concerns.
