How to turn up your water heater
A lukewarm shower has a way of exposing small household problems that are easy to ignore until they interrupt your routine. Learning how to turn up your water heater is one of those simple maintenance tasks that can make a noticeable difference, provided it’s done safely and with the correct temperature settings.
This guide walks you through the process for both electric and gas water heaters, explains what to check before making any adjustments, and highlights the mistakes that often leave homeowners frustrated. By the end, you’ll know exactly where to find the thermostat, how much to increase the temperature, how long to wait for results, and when raising the setting isn’t actually the solution.
Before You Start
You won’t need many tools, but a little preparation prevents unnecessary problems.
Gather these items before adjusting your water heater:
- A flat-head screwdriver (commonly needed for electric water heater thermostats)
- Work gloves
- Flashlight if the heater is installed in a dim utility room
- A cooking or digital thermometer to test hot water at the faucet afterward
Before making any changes, identify whether your unit is gas or electric. The adjustment method is different for each.
And check the manufacturer’s recommended maximum temperature if you still have the owner’s manual. Most households should keep the water heater around 120°F (49°C) because it balances comfort, energy efficiency, and protection against accidental burns.
If your household includes young children, older adults, or anyone with limited mobility, avoid increasing the temperature beyond recommended levels unless there’s a specific reason. Water hotter than 130°F can cause burns surprisingly quickly.
Step-by-Step Instructions
1. Identify Your Water Heater Type
Start by looking at the heater itself.
A gas water heater has a gas control valve near the bottom along with a pilot light or electronic ignition. An electric model has no gas line and instead features one or two access panels secured with screws.
Knowing which type you have saves time—and prevents trying to adjust the wrong component.
Many first-time homeowners mistake an electric heater for gas simply because both use large storage tanks. Take a minute to confirm before moving forward.
2. Turn Up a Gas Water Heater
Locate the temperature control dial on the gas control valve.
Most gas heaters don’t display exact temperatures. Instead, you’ll see labels such as:
- Warm
- Hot
- A
- B
- C
- Very Hot
Turn the dial slightly clockwise to increase the temperature.
Avoid jumping from the lowest setting to the highest in one adjustment. A small increase usually raises the water temperature enough without creating unnecessary safety risks.
But remember that every manufacturer labels these settings differently (which catches many homeowners off guard), so consult the manual if you’re unsure what each mark represents.
3. Turn Up an Electric Water Heater
Electric water heaters require a few additional steps.
First, switch off the corresponding circuit breaker in your electrical panel.
Never remove the access panel while power is still connected.
Use a screwdriver to remove the upper access panel. Fold back the insulation carefully until the thermostat becomes visible.
Using a flat-head screwdriver, rotate the thermostat slightly toward a higher temperature.
Many electric water heaters contain two thermostats—one near the top and another lower on the tank.
Adjust both thermostats to the same temperature. Leaving them mismatched can produce uneven heating and longer recovery times after multiple showers.
Replace the insulation exactly as it was, reinstall the access panel, and restore power at the breaker.
4. Wait for the Water to Heat
Don’t expect instant results.
A storage water heater usually needs anywhere from 30 minutes to two hours, depending on:
- Tank size
- Heater type
- How much hot water remains in the tank
- The amount of temperature increase
And using lots of hot water immediately after adjusting the thermostat simply slows the process because cold water enters the tank.
Patience makes a difference here.
5. Test the Water Temperature
Once enough time has passed, turn on the hot water at a nearby faucet.
Let it run for about two minutes before measuring the temperature with a thermometer.
Testing directly from the faucet gives a more accurate reading than relying solely on the thermostat setting because thermostat calibration isn’t always exact.
If the temperature is still lower than expected, make another small adjustment rather than a large one.
6. Fine-Tune if Necessary
Sometimes one adjustment isn’t enough.
If the water remains lukewarm after waiting the recommended amount of time, increase the setting slightly again and repeat the testing process.
The truth is, many homeowners assume the thermostat is inaccurate when the real issue is simply not waiting long enough for the entire tank to heat.
Make gradual changes until you reach a comfortable temperature.
7. Know When the Thermostat Isn’t the Problem
Raising the thermostat won’t fix every hot water issue.
If your water is still cool after increasing the setting, one of these may be responsible:
- Faulty heating element in an electric heater
- Broken thermostat
- Sediment buildup inside the tank
- Gas burner problems
- Undersized water heater for household demand
- Mixing valve issues
Or your heater may simply be nearing the end of its lifespan.
Most storage water heaters last between 8 and 12 years before performance starts declining.
Common Mistakes
The biggest mistake is increasing the temperature far more than necessary.
Many people assume hotter equals better. In reality, water above 140°F dramatically increases burn risk while also consuming more energy.
Another common problem is forgetting to shut off power before opening an electric water heater. Even though adjusting the thermostat looks simple, exposed electrical components can be dangerous.
Some homeowners only adjust the upper thermostat on electric models. If the lower thermostat stays at its previous setting, the tank heats unevenly, leading to inconsistent water temperatures during showers.
Waiting only ten or fifteen minutes before checking the faucet causes unnecessary confusion. Storage tanks need time to reheat the entire volume of water.
Here’s the thing: if your water heater suddenly stopped producing enough hot water after years of working properly, repeatedly increasing the thermostat often masks a mechanical issue rather than solving it. Realistically, that’s when inspection or repair becomes the smarter choice.
Finally, don’t overlook the insulation. After adjusting an electric thermostat, replace the insulation exactly as you found it. Leaving it loose or folded incorrectly reduces heating efficiency over time.
Tips to Do It Better
Small adjustments usually produce the best results.
Increase the thermostat by just one setting—or roughly 5 to 10 degrees—before testing again. Large jumps make it difficult to know which setting actually solved the problem.
Flush sediment from the tank once a year if your manufacturer recommends it. Mineral buildup reduces heating efficiency and shortens recovery time, especially in areas with hard water.
And if several people shower back-to-back every morning, consider adjusting your daily schedule before increasing the thermostat. Sometimes running appliances like the dishwasher later in the day provides more available hot water without raising the temperature.
Installing pipe insulation on the first few feet of hot water piping also helps retain heat between the tank and your faucets.
One honest limitation deserves mentioning: raising the thermostat cannot compensate for a water heater that’s simply too small for your family’s needs. If hot water consistently runs out despite proper settings, upgrading the tank capacity or installing a tankless unit may be the only lasting solution.
Frequently Asked Questions
What temperature should my water heater be set to?
For most homes, 120°F (49°C) is the recommended setting. It provides comfortable hot water while lowering energy costs and reducing the chance of accidental scalding.
How long does it take after adjusting the thermostat?
Most water heaters need between 30 minutes and 2 hours to fully heat the tank after changing the temperature.
Can I make the water heater much hotter?
Yes, but it’s generally not recommended unless there’s a specific household need. Temperatures above 130°F increase the risk of burns and use more energy.
Why is my water still cold after turning up the thermostat?
The thermostat may not be the issue. Faulty heating elements, sediment buildup, burner problems, or an aging water heater are common causes of poor hot water performance.
Should both thermostats on an electric water heater match?
Yes. Setting both thermostats to the same temperature helps the heater warm the tank evenly and improves recovery after heavy use.
Final Thoughts
Knowing how to turn up your water heater isn’t difficult, but making small, careful adjustments is far more effective than immediately choosing the hottest setting. Whether you own a gas or electric model, following the correct sequence keeps the process safe and helps you avoid the common mistakes that waste time or create unnecessary risks.
Your next step is simple: identify your water heater type, adjust the thermostat slightly, wait for the tank to recover, and verify the temperature with a thermometer before making any further changes
