Turn Down Your Water Heater: The 5-Minute Fix Most Homes Skip

Your water heater is probably the most ignored appliance in your house. It sits in a closet, a basement or the garage, quietly keeping a whole tank of water hot around the clock, whether you're in the shower or asleep or on vacation. And there's a decent chance it's keeping that water hotter than you ever need.

Turning it down is one of the easiest energy fixes you can make. There's nothing to buy and nothing to install. You need a kitchen thermometer and a few minutes, plus a little patience while the tank adjusts. The free method is below, and there's an optional upgrade box for anyone who wants to go a step further.

Why it's worth doing

The U.S. Department of Energy says most households only need their water heater set to 120°F, and it notes that some manufacturers set tanks at 140°F. That gap matters. A tank-style heater keeps its water hot all day and night, and hotter water loses heat faster through the tank walls and the pipes. Every time the temperature drops, the heater fires back up to replace the lost heat. Turn the setting down, and it spends less energy just standing by.

There's a safety bonus too. Lower temperatures reduce the risk of scalds, which matters most in homes with small children or older adults who may not pull away from hot water as quickly. Most people won't notice the difference in the shower, since you're mixing in cold water anyway, though a big household that runs the tank dry may find the hot water runs out a little sooner.

The free way, step by step

Step 1: Figure out what kind of water heater you have

Look at the label on the tank. It tells you the fuel type, and often includes instructions for adjusting the temperature. Most homes have one of these:

• Gas tank. A tall tank with a burner at the bottom and a metal flue pipe coming out the top. The thermostat is a dial on the gas control valve near the bottom.
• Electric tank. A tall tank with a power cable instead of a gas line and flue. The thermostats are usually hidden behind one or two access panels on the side.
• Tankless or heat pump. These usually have a digital display or control panel. Check the manual for how to change the set temperature.

Step 2: Test your current water temperature

Before you touch any dials, find out where you're starting. The dial markings on many heaters aren't exact, so a real measurement beats guessing.

1. Pick the faucet farthest from the water heater. That's where the water has traveled the longest and lost the most heat.
2. Turn on only the hot water and let it run until it's as hot as it gets and stops warming up.
3. Fill a glass or mug and put a kitchen thermometer in it. Wait for the reading to settle.

Write down the number. If it's well above 120°F, you have room to turn it down. If it's already near there, you're in good shape, and you may only need to check the vacation mode and drips in steps 5 and 6.

Step 3: Adjust the thermostat

Gas tank: Find the dial on the gas control valve near the bottom of the tank. Many aren't labeled in degrees at all. You'll see words like warm, hot and vacation, or a set of letters or marks. Check the label on the tank or the manual to see what each mark means, then turn the dial a small step toward cooler. You don't need to turn off the gas to adjust the dial.

Electric tank: This takes a little more care, because the thermostats sit next to live wiring.

1. Turn off power to the water heater at the breaker box. Confirm it's off before going further; a non-contact voltage tester is the easy way to check.
2. Remove the access panel or panels with a screwdriver. You'll usually find insulation and sometimes a plastic safety cover inside.
3. Move the insulation aside gently to reveal the thermostat. Many electric tanks have two, an upper and a lower. Set them to the same setting.
4. Turn the adjustment screw a small step toward cooler with a flat screwdriver. Don't touch any wires or terminals.
5. Put the insulation and panels back, then turn the power back on at the breaker.

Step 4: Wait, re-test and fine-tune

The water in the tank doesn't change temperature instantly. Give it a few hours, ideally after the household has used some hot water so fresh water gets heated to the new setting. Then repeat the test from step 2 at the same faucet.

Too hot still? Turn it down another small step. Too cool? Nudge it back up. Aim for around 120°F at the tap, the level the Department of Energy says most households need. It may take two or three rounds to get it right, but you only have to do this once.

Step 5: Use vacation mode when you're away

If you're leaving for a few days or more, there's no reason to keep a full tank hot for nobody. Many gas water heaters have a vacation setting on the dial, and many electric, tankless and heat pump models have a vacation mode on the controls. If yours doesn't, turn the dial to its lowest setting. When you get home, set it back to your marked spot. It's worth adding to your vacation energy checklist.

Step 6: Fix hot-water drips

A dripping hot water faucet sends heated water straight down the drain, a drop at a time, and your water heater has to replace every drop. Check the kitchen and bathroom faucets and the shower. Many drips come from a worn washer or cartridge, which is often a cheap part and a simple repair. In a rental, report it to your landlord. The same goes for a slow leak at the tank itself: water pooling around the base is a sign to call a plumber.

A few things to check before you go lower

• Your dishwasher. Look at the manual. Some dishwashers need hotter incoming water to clean well unless they have a built-in booster heater that warms the water on its own. If your dishes start coming out less clean, this is the first thing to check.
• Your household's health. Water heaters kept too cool can let bacteria such as Legionella grow in the tank. That risk matters most for anyone in the home who's immunocompromised.
• Your heater type. Tankless heaters only heat water as it flows, so there's no stored tank losing heat. Turning one down can still keep water from coming out hotter than you need, but check the manual for recommended settings.

Mistakes that make it harder than it needs to be

• Trusting the dial. Dial markings are often approximate. Measure at the tap before and after.
• Testing too soon. Right after you adjust it, the tank is still full of water at the old temperature. Wait a few hours.
• Making one big change. Small steps let you find the sweet spot without ending up with lukewarm showers.
• Setting the two electric thermostats differently. On a two-element electric tank, keep the upper and lower thermostats at the same setting.
• Skipping the breaker. Never open the panels on an electric heater with the power on. It's not worth the shortcut.

Renters and apartments

If your water heater is inside your unit and you pay for the energy that runs it, you can usually adjust it the same way, though it's polite to check your lease or ask your landlord first. If the heater is shared or in a locked utility room, you can still test the tap temperature and ask building management if it's set higher than needed. And you can always fix habits: run full loads in the dishwasher and try washing laundry in cold water, which cuts hot water use without touching the heater at all.

When the upgrade is worth it (and when it isn't)

An insulation blanket can help an older tank that feels warm to the touch, especially one sitting in a cold basement or garage. But check first: some newer tanks are already well insulated, and some manufacturers advise against adding a blanket. Read the label on the tank and the manual. On any tank, don't cover the thermostat access panels or the relief valve. For gas tanks, also keep any blanket clear of the top, the flue, the burner area and the controls, and follow the blanket's instructions exactly.

Foam pipe insulation is a good buy if you can easily reach the hot water pipes near the tank, especially where they run through an unheated space. It's cheap, it slips on, and it helps hot water arrive a little warmer at the tap. On a gas water heater, keep foam sleeves well away from the hot flue pipe.

An instant-read thermometer is worth it if your kitchen thermometer is slow or hard to read. Otherwise, the one you have is fine.

Skip the blanket if your tank's label or manual advises against it, or if the tank feels cool on the outside. That's a sign it's already well insulated.

The bottom line

Turning down your water heater is about as close to free money as home energy gets: measure, adjust, re-test, done. You'll keep the tank from working harder than it needs to, lower the scald risk in your home and probably never notice the change in the shower.

Want to find the next easy fix? Walk through our DIY home energy audit to see where else your home is using more energy than it needs.