Your water heater is an essential home appliance that helps you cook, bathe, wash dishes, shower, do laundry, and more. To keep your water safe, it’s important to set your unit to the correct water temperature and make sure it’s functioning properly. Here’s what you need to know:
Understanding Your Temperature Settings
Whether you have an electric or gas-powered tank or tankless water heater, you’ll want to make sure it’s set to provide you with clean water that is hot enough to serve your needs. Most people prefer to set their heaters between 120°F and 140°F, which will keep the water safe and pleasantly warm. Keeping your water heater at 140°F, the default setting on many heaters, will prevent harmful bacteria from growing in the tank. Unfortunately, this setting can also use more energy and could wear out your heater faster.
The U.S. Department of Energy recommends setting your water heater to 120°F to save energy and prevent accidental scalding, but most people prefer to set it a bit higher. Whatever you do, never use a setting below 120°F. Lower water temperatures can allow dangerous bacteria, including legionella, which causes Legionnaires disease, to grow inside the storage tank.
Other factors you should consider in setting your temperature:
- If your household includes people who are susceptible to burns, like elderly people or young children, set your water heater on the low end of the temperature range.
- If someone in your household is immunocompromised or you use a dishwasher without a heating element, consider setting your water heater closer to 140°F.
- If you’re trying to save money, lowering your water heater’s temperature setting by 10°F can reduce your energy consumption by 3% to 5%. Just remember that you need to balance frugality with keeping your water at a safe temperature.
How Water Heaters Keep Water Hot
Electric tank water heaters use heating elements in the top and bottom of the tank to heat up water and keep it hot. Gas water heaters transfer heat to water from their burners. Either way, the heating elements must be in good shape to heat your water properly.
If your water heater’s temperature control malfunctions or fails, your water may become too hot or too cold. In some cases, the heating elements will fail to turn off when the water reaches the correct temperature; in other cases, the heating element might fail to turn on.
Tankless water heaters use an electric element or gas burner to heat water on demand when you turn on a hot water tap. If its sensors, controls, or heating components malfunction, the heater may not be able to deliver water at the correct temperature.
How to Adjust the Temperature of Your Water Heater
Whatever kind of water heater you have, you should be able to set it to the temperature you desire, or call a plumber to do it for you. Here’s how to manage it:
Gas-Powered Tank Water Heaters
To set the temperature on your gas water heater, find the control knob and turn it to the appropriate setting. Some units use symbols instead of numbers to mark the different heat levels, so make sure you understand what the symbols mean. You’ll want to start by looking for a triangle setting that stands for “hot,” which should be 120°F. Beyond this marker, you may see settings marked “A,” “B,” “C,” and “very hot,” each of which should raise the temperature by 10°F.
Take care to use the right temperature setting—an image of one or two dots beside a triangle is generally a “low” or vacation mode setting that reduces or turns off the heat, allowing the water to fall below a safe temperature.
Electric Tank Water Heaters
Some electric water heaters have a visible, adjustable thermostat, but many have temperature controls that are hidden behind a screwed-in access panel. If you need to adjust the temperature, go to your main circuit breaker panel and shut off power to the heater before you take off this cover. To adjust the temperature, you’ll need to use a flat-head screwdriver to set the temperature control, then replace the access panel cover and turn on the electricity.
Tankless Water Heaters
Tankless water heaters usually have digital control panels that make it easy to adjust the temperature. Press the up or down buttons until the desired temperature is visible on the display panel.
Testing Your Water Temperature
Water heaters don’t include built-in thermometers, so there’s no way to directly measure the temperature of the water in your tank. Older water heaters may be more likely to have problems regulating the water temperature, so if your water seems colder or hotter than it should be, pay attention.
You’ll want to try to measure the temperature of the water coming out of the tank by following these steps:
- To make sure that your tank is full of heated water, let the tank sit idle and don’t use any hot water for at least an hour.
- Turn on the hot water tap and let the water flow until it reaches its maximum temperature, then use an instant-read kitchen thermometer to measure its heat level.
- If the water temperature doesn’t match up with your water heater’s temperature setting, call a professional plumber to check out and repair your heater.
Most of the time, once you find a water temperature that works for you, you can set it and forget it. You can also install accessories like water tank boosters that keep your water at 140°F but deliver cooler water at the tap. If it takes a long time for hot water to reach your tap, you can invest in a circulating system that keeps hot water in your pipes. Your plumber can help you look into options that will serve you best.
For Perfectly Hot Water at Home, Trust the Professionals at Benjamin Franklin Plumbing
Setting your water heater to the right temperature and keeping it in good working order is key to maintaining a safe and comfortably hot supply of water at home. The experts at Benjamin Franklin Plumbing will be delighted to help you keep your water heater well-maintained so that your water temperature will always be just right.