How To Set Your Water Heater Temperature

How to Set Your Water Heater Temperature the Right Way

Setting your water heater temperature is simple, you turn the knob. But wait, where is that knob? How much should you turn it? How can you set it so that you use the least amount of energy and still not run out of hot water in your shower or bath? This article will answer those questions.

On a gas water heater the thermostat is on the gas valve at the front of the water heater. It looks like this:

On an electric water heater there are usually two and they are under two covers on the side of the water heater. Be sure to turn off the power to an electric water heater before opening these panels.

The main objectives in setting the temperature are three fold. One is to have enough hot water for the activities you use hot water for (shower, bath, dishes, etc.) and not run out. The second it to set the temperature as low as possible so that you use the least amount of energy possible. The third is to set a low enough temperature to prevent scalding.

The reason that setting the temperature of the water lower conserves energy is that much of the cost of running a hot water heater is the ‘standby losses’. Standby loss is the heat that is lost by just having a tank full of water sitting in your house. It’s like putting boiling water in a thermos. The thermos will keep the water hot for a while, but if you come back to it later the water in the thermos will be cooler than when you put it in there. You would have to continually add heat to maintain the same temperature. If you had two thermos’ with boiling water and put one on the counter and one in the freezer and you came back 4 hours later the water in the thermos that was in the freezer would be much cooler than the water in the thermos on the counter. This is because the temperature difference between the inside of the thermos and the temperature outside the thermos is what ‘drives’ the heat out of the thermos. The greater the temperature difference the faster the heat loss. It is the same for your water heater. The higher the temperature the faster heat is lost through the insulation around the outside of the tank, and the more frequently the burner has to come on to maintain the higher temperature inside. The more the burners are on the higher your costs. So, to use the least amount of energy when the water is just sitting there you should set the thermostat as low as possible.

The problem with setting the thermostat lower is that you will run out of hot water faster. Hence, the shower water goes cold or there is not enough hot water for a nice bath. Neither of these options are acceptable so how do you optimize the thermostat setting so that it’s as cool as possible to save as much energy as possible and also hot enough to provide enough water for people to take showers?

Well, here’s how you do it starting with the temperature set where it is:

If you still have hot water at the end of your shower turn the thermostat on your water heater down one notch. If you still have hot water at the end of your shower the next day, turn it down one more notch. Do this until you have one day when the hot water does not last long enough in your shower. I know this isn’t going to be a pleasant experience, you’re tough though, you can do it! The next day you’ll be back to hot water that lasts because what you do then is turn the thermostat up 1/2 to 1 notch. Then you will have set your thermostat to the perfect temperature.

If you always run out of water at the end of your shower you can turn the temperature of the water heater up 1/2 to 1 notch at a time until you’ve found the perfect temperature. You can also do one of the tips listed below.

There may be times when you need more hot water like when you have house guests, want to take a bath when you normally shower, etc. The trick here is to turn the temperature of your water heater up about an hour before you will need it. Also, leave yourself a note to turn the thermostat back down when you’re done.

Lastly, to prevent scalding, especially if you have small kids in the house, keep the temperature of the water heater as low as possible.

Other tips:

  1. Don’t run the dishwasher within 2 hours before you regularly shower or take a bath. It uses hot water too.
  2. Install a water-saving shower head. These shower heads have a small orifice that will only let so much water through them at a time thus saving you money by using less water and extending the time that hot water is available.
  3. Install a valve at your showerhead so that you can lower the volume of water that comes out of your showerhead yourself. You can turn the water off or down while you suds up then back on to rinse off without having to reset the temperature.
  4. Set the thermostat to the ‘vacation’ setting when you will be away from home for a couple of days or more. Leave yourself a note to turn the temperature back up when you return so you don’t get a cold surprise.

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