If you search online for the best water heater temperature setting, you’ll find multiple answers. There will be many different arguments for and against a temperature setting. I doubt many studies have been done. But I can give you my two cents.
The best water heater temperature setting.
After 27 years in the plumbing trade, I’ve seen a lot. The temperature setting on your water heater is a personal decision. But what factors dictate the best water heater temperature setting.
- Comfort – Your preference.
- Water heater recovery – Lower temperature settings are easier to maintain.
- Disease – Lower water heater temperature settings may promote disease.
- Scalding – Children & special needs people can be scalded.
- Energy efficiency – The hotter the temperature the lower the efficiency.
- Calcification – The higher the temperature the faster hard water deposits in the tank.
My professional opinion is that 120 degrees is optimal for water heaters.
Why set water heater’s temperature to 120 degrees?
As a plumber, I’ve found that most people can be comfortable with a hot water temperature of 120 degrees. If you want a hotter shower, just take shorter showers and set the temp higher.
Most manufacturers recommend a setting of 120 degrees for the calculated recovery time. This just means the water heater will keep up better at this temperature.
I’ve not heard of anyone in my customer base getting ill due to a low water heater temperature setting. That doesn’t mean it hasn’t happened. But it’s pretty unlikely.
The reason I usually mention for keeping the temperature setting to 120 degrees is to protect kids from scalding themselves. This also applies to seniors and disabled folks.
I know that energy efficiency kind of goes out the window when you’re only talking about 3 to 5 percent savings over a year for every 10 degrees lower it’s set. But we all do want to be environmentally responsible where we can.
The other important reason I mention for keeping your water heater temperature at the manufacturer’s recommended setting, is it will extend the life of your water heater. The hotter it’s set, the faster hard water deposits in the bottom of gas water heaters or on the electric water heater heating elements.
It can be difficult to adjust the temperature on a standard water heater. If I’ve ever worked on your homes plumbing you’ve probably heard me snivel about plumbing manufacturer engineers. They just don’t seem to be able to translate their ideas to real world problems. So they over complicate a simple thing.
Plumbing is simple. Plumbers are simple. Let’s keep it that way. But for now, let’s look at how to adjust the temperature on your standard water heater.
How to adjust the temperature on electric water heaters.
An electric water heater actually has two temperature settings. They have an upper and lower heating element, so they have an upper and lower thermostat.
And although they’re made unnecessarily difficult to access, they do at least put numbers on the dials.
You’ll need to remove an upper and lower tin cover, and there is usually a bit of insulation covering the thermostat. You can just move the insulation out of the way.
You’ll use a flathead screwdriver to raise or lower the temperature. Set both thermostats to the same temperature: 120 degrees.
Don’t forget to replace that piece of insulation before closing it all up, because it can save you energy loss.
How to adjust the temperature on a gas water heater.
For some reason unknown to me, manufacturers insist on making this complicated. If you look at the gas valve at the base of your gas water heater, you’ll see the round temperature dial. The labels on them aren’t in degrees. Instead, they have either arrows or letters.
As a rule, line the arrows up with each other or set the arrow on hot.
The “A”, “B”, and “C” settings above that are higher temperatures in 10 degree increments.
Do you have to unplug a water heater to adjust the temperature?
You should turn off power to the water heater at the circuit breaker before adjusting the thermostat. This means effectively “unplugging” the heater by switching off the electrical circuit to prevent any risk of electric shock.
To change the thermostat on an electric water heater:
- Shut off power at the circuit breaker
- Remove the access panel covering the thermostat
- Use a screwdriver to adjust the temperature setting
- Replace the access panel
- Restore power
To change a gas water heater thermostat:
- Turn off the gas supply using the dedicated gas valve near the water heater
- You do NOT need to fully unplug or disconnect the heater
- Ensure good ventilation in the area
- Locate the gas control valve (usually near the bottom of the tank)
- This valve typically has a temperature dial or knob
- You can adjust the temperature directly on this dial without draining the tank
- Settings are usually marked with temperatures or ranges like “Low”, “Medium”, “Hot”
Important Cautions:
- If you smell gas at any point, stop and ventilate the area
- Some newer gas water heaters might require removing an access panel to reach the thermostat
- If you feel unsure about any step of this process, please contact a professional
Do you have to drain electric water heater to change thermostat?
You do NOT need to drain the water heater to change the thermostat temperature setting. Draining is only necessary for maintenance like flushing sediment or replacing heating elements.
You don’t need to drain it to change the water temperature on a gas heater either.
When to adjust your hot water heater.
A water heater should normally just be left alone. The plumber that installs water heaters will set it up. But if you’re leaving your home for an extended period, it might be worth setting the temperature to its lowest setting. It’ll save you money.
And sometimes, if it’s an exceptionally cold winter, you might want to raise the water temperature up 10 degrees to compensate for the colder water supply.
And of course, if your living situation changes (say there are no longer young children in the home), personal preference may convince you to up the temperature if you really like to boil in the bath like a little crawfish.
Who to call for water heater repair and installations in Lee’s Summit, MO.
You’ll find that other trades advertise water heater installation and repairs. But if you want a qualified water heater tradesman, call a plumber.
We know how to install and repair water heaters. We also know why it’s done that way, and are experts on the many safety considerations.
For more information, please check out the Advocate Master Plumbing water heater services page.
