What is the lowest setting on a hot water heater?

Author: Carey Toy  |  Last update: Sunday, June 1, 2025

Most water heaters are designed to operate safely at temperatures between 120 and 160 degrees. Many tank-style units also have a low-temperature setting where the unit will only heat up the water to around 90 to 100 degrees.

What is the lowest you can set a water heater?

And while there is a very slight risk of promoting legionellae bacteria when hot water tanks are maintained at 120ºF, this level is still considered safe for the majority of the population. If you have a suppressed immune system or chronic respiratory disease, you may consider keeping your hot water tank at 140ºF.

Is 120 too low for a hot water heater?

120 degrees F is the recommended setting for your water heater. This is to prevent scalding injury to children. On the other side, you require more hot water if it's at a lower temperature. Plus dishwashers need to heat the water if it's below the...

What does a and b mean on a water heater?

Understanding these settings can help when figuring out how to adjust the temp on water heater units. A typically represents around 130°F. B usually corresponds to 140°F. C indicates a temperature of about 150°F or higher.

What temperature is the C setting on a water heater?

That should be plenty hot enough for most uses in your home. Now, some water heater temperature controls come with settings that read “A-B-C” as opposed to numbers. Generally, A means 120 degrees, B means 130 degrees, and C means 140 degrees. Refer to your water heater's manual to confirm these settings.

Does a Water Heater Really Need to be Drained and Flushed?

Should I set my water heater on AB or C?

These are usually labeled A, B, C or 1, 2, 3, and the last setting is always “Very Hot.” The A or 1 setting should be around 130 degrees, B or 2 is 140 degrees, C or 3 is 150 degrees and “Very Hot” is always 160 degrees. Again, we never recommend setting the unit above the B or 2 setting to prevent scalding.

What is the low temperature on a water heater?

What Temperature Should a Water Heater Be Set At? Most water heaters are designed to operate safely at temperatures between 120 and 160 degrees. Many tank-style units also have a low-temperature setting where the unit will only heat up the water to around 90 to 100 degrees.

What mode should my water heater be on?

So, what is the best temperature range for your water heater? The EPA recommends 120 degrees because it's hot enough to keep diseases at bay but not hot enough to cause scalding. This setting will also supply enough hot water for most small families and is relatively energy efficient.

What is the best setting for a hot water heater?

120 degrees Fahrenheit is the safety recommendation against scalding, but 140° is the common default setting. Most experts agree that anything below 120 degrees creates a risk for bacteria to develop inside your water heater from stagnant water, such as legionella that causes Legionnaire's disease.

What is temp B on water heater?

B - 140° F - Less than 5 seconds. A - 130° F - About 30 seconds. HOT - 120° F - More than 5 minutes. LOW - 80° F - No hazard.

Is it better to set the water heater to low or high?

If you opt to lower your water heater temperature, additional savings can come from the reduced energy required to heat the same amount of water to 120 degrees instead of 140 degrees. Experts also recommend turning down your water heater to its lowest settings if you plan to be away for an extended period.

What should my hot water tank thermostat be set at?

The recommended setting for this control is 60°C/140°F. (Storing hot water at temperatures of less than 55°C is not advisable due to potential for Legionnaires disease). If the water coming out of your taps is too hot then check this control as it could be set too high.

What is the most economical setting for hot water?

Top free tips to save on your water heating
  • Turn down the thermostat on your cistern to 60-65°C.
  • If you have an old central heating system, the temperature of the hot water will be determined by the internal circulatory system, as set on the boiler, so turn that down.
  • Use a kettle for the times you need very hot water.

What happens if water heater is set too low?

If it's set too low, not only will your hot water feel lukewarm, at best, it can also lead to bacterial growth which can cause things like Legionnaires' disease.

What is the lowest heater setting?

55 — 65°! If you're going on vacation, we suggest leaving the thermostat set to 50° F. Any Heating contractor will tell you that the Barest Minimum you should have your thermostat is 50 degrees Fahrenheit in order to protect the water pipes. I suggest a minimum of 55 degrees.

Is 120 too low for water heater?

The maximum Department of Energy recommended water heater temperature setting you should never exceed is 140 degrees Fahrenheit. The lowest recommended setting should never be below 120 degrees Fahrenheit.

Is 110 degrees too low for a water heater?

We recommend always keeping the heater set between 110 and 120 degrees. In the summer, try setting your water heater temperature at the low end of this scale, placing it close to or at 110 degrees.

Does turning up the water heater make hot water last longer?

Raising the temperature setting on your water heater ultimately makes your hot water supply last longer. It will ensure everyone gets a hot shower, with plenty leftover to run your dishwasher and washing machine.

What temperature should hot water be for shower?

According to most dermatologists, the ideal shower temperature is anywhere between 98°F (37°C) and 104°F (40°C)—and no more than 105 °F (41°C). Rinsing under lukewarm water allows you to stay comfortable and maintain your body temperature while reaping all the benefits of both hot and cold showers.

What is the most efficient setting for a hot water heater?

What Temperature Should a Water Heater Be Set At? Most water heaters are set to a standard temperature of 140 degrees Fahrenheit. However, the Department of Energy notes that turning your water heater temperature down to 120 degrees Fahrenheit can help save energy.

What setting should I have my hot water on?

The thermostat on your hot water cylinder should be set between 60 and 65 degrees. Setting it any higher than this means you're using more energy than is needed. Not only that, but you risk scalding yourself when using the hot water tap or shower.

Why is my hot water not as hot as normal?

Inspect the thermostat, which controls hot water heater temperature. If someone has recently changed the setting, that could be the reason behind your lukewarm water woes. However, if the temperature setting is correct, the thermostat itself might be broken. You can have the thermostat replaced fairly inexpensively.

What is low temperature hot water?

Low Temperature Hot Water systems operate within a temperature range typically spanning from 60°C to 93°C. This makes them ideal for applications where moderate heat is sufficient. LTHW systems are commonly employed in residential buildings, schools, offices, and other settings where standard space heating is required.

What should the bottom thermostat be set at in a water heater?

Set both thermostats to 120°F. If higher temperatures are required turn the water temperature dial clockwise ( >>) to increase the temperature.

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