Informational Guide

How To Turn Up Water Heater (2024 Adjustment Guide)

by Andrew

Water heaters do exactly as it says on the tin; they heat water. They provide economical hot water for cleaning, showering, and cooking, and are one of the most important systems in your home.  

As the cold winter nights draw in, it's comforting to add a few degrees to your water heater so you can warm up more quickly. In this guide, we'll explain how to turn up a water heater and what the best temperature settings are for your home. 

There are several different types of water heaters, but they are usually all easy to adjust. You should start by getting an accurate gauge of what your water temperature is now by running your hot water tap until it's as hot as it can go and holding a thermometer underneath it for 30 seconds.

Once you have an accurate reading, you’ll know the current temperature and be able to test if you’ve raised the temperature of your water heater as needed.  

Many modern water heaters are user-friendly, and you'll be able to adjust them without any work at all. You should always check your water heater and see if there's a visible dial or control. If there is, adjust it until it reaches the desired temperature.  

If there aren't any visible controls, then you'll need to do a bit more work, but it's still simple. Make sure you have a flathead screwdriver and a Phillips screwdriver, and then follow the steps below depending on which type of heater you have: 

Gas Water Heater 

  1. 1
    Start by turning off the power to the water heater at the circuit breaker. It’s really important that you do this so you can adjust it safely and remember that even though it’s gas-powered, it will still be connected to your mains.  
  2. 2
    Locate the access panel which covers the thermostat. Use a screwdriver to remove the panel.  
  3. 3
    Remove the insulation by peeling it back. 
  4. 4
    Use a flathead screwdriver to adjust the thermostat temperature. You should see it change as you turn the screwdriver one way or another. Keep going until you reach the desired temperature. Some water heaters have two thermostats, so you’ll need to adjust them both to the same temperature.  
  5. 5
    Replace the insulation and the access panel on the water heater. 
  6. 6
    Turn the power back on and make sure it's fully functional. For gas heaters, you may need to relight the pilot light to get it working, or it may relight automatically.  
  7. 7
    Test the water temperature by letting hot water run for a few minutes and holding a thermometer under it. Hopefully, it's reaching the right temperature; if not, you'll need to open up the thermostat again to check everything. 

Electric Water Heater 

  1. 1
    Turn off the electricity at the breaker 
  2. 2
    Locate and remove the thermostat access panel. This is normally easy to find and located on the outside of the heater.  
  3. 3
    Adjust the temperature using the flathead screwdriver to move the dial from high to low. This is typically labeled, but you may need to consult the user manual. 
  4. 4
    Once you're happy with the setting, seal the access panel back up and screw it on tightly.  
  5. 5
    Turn the power back on so your water heater is working again. Leave it 2-3 hours. 
  6. 6
    Run the water until it's as hot as it can go, and hold a thermometer underneath to test it. Hopefully, it's risen as much as you wanted, but you can always go back to the thermostat if not. 

Hybrid/Heat Pump Water Heaters 

Hybrid water heaters work by using some natural heat from the outside environment to warm your water, along with electrical power to do the rest of the heating. They work well in hot areas and can be an effective way to lower your bills.  

The thermostat is usually controlled electronically, and therefore you need to follow the same steps as the electric heater. Most hybrid water heaters are modern, so you may well have an external control panel or dial to adjust the temperature easily. 

Solar Powered Water Heater 

Solar powered water heaters use the heat generated from the sun to warm your water. This, combined with some electrical heating, gives you an adequate hot water supply for a small family, but won't work as well for larger homes.  

  1. 1
    Start by disconnecting any power sources from the water heater. Turn off the electricity to the breaker and make sure no power is running to the heater when you start work.  
  2. 2
    Locate the thermostat access panel and remove it. 
  3. 3
    Use your flat head screwdriver to adjust the dial to the left and right. This should be labeled and clear whether you're increasing or decreasing the temperature.  
  4. 4
    Reattach the access panel and turn the power back on. 
  5. 5
    Leave the water heater for 2 hours to warm up and then test the temperature to make sure it’s risen 

Correct Temperature Range Of Water Heaters 

We're all more energy conscious than ever before, and homeowners know that it pays to understand where you're paying the most. Your water heater accounts for roughly 20% of your home energy bill, which is significant already, but if you set your water heater too high, you'll end up paying a lot more each month.  

Conversely, if you set your water heater too low, then you risk having cold showers, and it can lead to stagnant water gathering in the system. This can eventually lead to bacteria building up in the water heater and can impact your family's health.  

120 degrees Fahrenheit is the recommended temperature for your water heater because it's hot enough to kill bacteria but isn't hot enough to scald you. For small families, this is ideal, and it should mean you're all able to get hot showers without spending a fortune on your energy bills.  

If you want to save money, or if you live alone, then you may opt to lower the temperature. You’ll shave about 5% off your energy bill for every 10 degrees you reduce your water heater by, which can mean significant savings throughout the year. If you have young children, then you may also decide to turn it down because even a few seconds at a higher temperature can badly damage an infant’s skin. 

If you have a dishwasher that needs heated water or a larger family, then you may need a higher temperature. Those with particular health conditions may also need hotter water to help protect them from infection. In these cases, we recommend going up to about 140 degrees, but no higher.  

In general, you should keep your water heater at 120-160 degrees Fahrenheit to balance efficiency with effectiveness. 

Thermal Switch Water Heater

Can You Turn Up The Temperature of Your Water Heater? 

Yes, almost every single water heater can be adjusted so you can get the temperature you want. Typically, water heaters are turned up in winter and down in summer, but some homeowners decide to permanently raise or lower the temperature based on their needs.  

If you choose to increase the temperature, it can be more comfortable, and it lowers the risk of bacteria growing in your water tank, but it will cost you more. On the other hand, if you choose to lower the temperature, you will save money on your energy bills, but you might not have hot enough water. 

There are quite a few reasons to turn up the temperature of your water heater, and it's usually very straightforward to do yourself.  

Increasing The Temperature of Popular Water Heater Models 

We’ve given some general guidance on how to increase the temperature of your water heater, but every model is different. Here’s a quick guide of how each of the popular manufacturer’s water tanks should be adjusted: 

Rheem Water Heaters 

Rheem water heaters are reasonably straightforward, and you’ll just need to undo two screws at the top to remove the cover and access the thermostat. However, some larger Rheem models have two access covers and two thermostats, so you’ll need to make sure you adjust both to increase the temperature.  

rheem water heater installing

AO Smith Water Heaters 

There’s a wide variety of AO Smith water heaters, but they're all reasonably easy to adjust. For tank models, you'll find most AO Smith water heaters have two thermostats which will both need to be adjusted so they match, rotating the dials clockwise to increase the temperature. For tankless models, it's the same process, but you won't need any tools to remove the access cover.  

Bradford White Water Heaters 

Bradford White water heaters are easy to adjust, and you can follow the steps for any electric heater. However, bear in mind that Bradford White water heaters can't be set below 120 degrees Fahrenheit but can be set to go over 160 degrees Fahrenheit if you decide you need it a lot hotter.  

Whirlpool Water Heaters 

Whirlpool is one of the most well-known brands on the market, and their water heaters have a good reputation. There's no special trick to adjusting the temperature on a Whirlpool model, but there is usually a lower and upper access panel and a thermostat behind each. You'll need to remove both panels and adjust both thermostats to increase the temperature.  

Rinnai Water Heaters 

Rinnai water heaters generally have a control panel on the front, so it's very simple to raise the temperature without any work. If not, you'll need to open up the front access panel by removing 4 screws located on the corners of your heater. Then, find the dip switches inside which connect to your circuit panel. You'll need to flip the correct switch to get the temperature, but to raise the water heater to 140 degrees, it will be switch 5, and 160 degrees it will be switch 6. Make sure you check the user manual to make sure you use the correct switches and get the right temperature.  

Navien Water Heaters 

Many Navien water heaters come with remote controls so you can adjust the temperature at the push of a button. If not, you’ll need to remove the access panel and use the dip switches within the water heater to raise the temperature. It should be reasonably clear which switches you need to flick, but you can check the user manual for more information. 


Why is my hot water not hot enough? 

This is usually because your water heater is set too low, so you'll need to adjust the thermostat. However, if the problem persists, it could mean that there is an issue with your machine, and you’ll need to get a professional to come and check it out.  

Is 140 too hot for a water heater? 

Most manufacturers set their water heaters at 120 or 140 degrees. 140 degrees is about right for most families, but young infants or the elderly might benefit from a slightly lower setting.  

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

No, the volume of water won't change, but it will give you consistently hot water for longer while you shower.  

How long does it take a water heater to heat up? 

It usually takes about 30-40 minutes for a water heater to heat up, but some older, larger models can take several hours.  


Having your water heater configured correctly is the key to staying warm and comfortable this winter. It's important you keep it set to the right temperature so you can have the best showers without driving your energy bills up too high.

Hopefully, this guide has helped explain how you can adjust your water heater temperature so you can give yourself a few extra degrees of warm water when it’s really needed.