Thermostat went whack-a-doodle on our electric water heater and we were getting scalding water out of the taps.

Easily fixed, new 'stats top and bottom. But now I'm wondering what the most efficient setting is:

Question:
Which is more efficient:

Choices:
Higher set temp, use less water in the mixing valve.
Lower set temp, use less electricity heating it up.
It's a wash.
Wait...you heathens have indoor plumbing up there?
Other (explain in post)

 

Off would be the most efficient, assuming you can live without hot water!

Use lower temp for every day, and only turn it up if it can’t keeps up or special circumstances (eg you have house guests staying with you).

quote:

Originally posted by tsmccull:
Off would be the most efficient, assuming you can live without hot water!

You beat me to it!

flashguy

Oil, natural gas or propane.

Thermostats top and bottom, I am guessing they control electric elements.

With electric, I would adjust as low as possible and still getting all the hot you want/need. If guests arrive they would need temporary increases. Set them back after leaving.

I make a point of turning my water heater off if we leave for a week or so. No need to heat water for nobody.

You could also have a timer installed into the system to turn the heater off when the water isn’t being used. IE, it could be off from 8 - 3 if nobody is home during the day. At 3 it goes on and brings the water back up to normal temperature. This may help in electric costs. If the heater is on most of the time, the timer wouldn’t be much use.

Stop heating water 24/7, go to an on-demand is much better, but don't go electric, gas is the only way to go.

The elements should draw about 18.6 amps. If they draw a lot lower it will trick the thermostat into staying on. If it overheats again that is the first thing to check, usually the lower goes.

My hot water heater just failed. I replaced it with a Rheem platinum with the 12 year warrantie and the digital in t.f deface. I added the wifi module that I can set the temp anywhere with my phone. When the wife and I are gone, I should be able to turn it off easily and back on with my phone!

It's probably trivial. I go with hot but not so hot that a couple seconds under just that side would require medical attention.

Lower set temp. Difficult to explain, but in math it's something called a differential equation where energy comes in and energy goes out, sometimes the rate of input and output changes, but that said Lower set temp is best for saving energy overall since maintaining the a higher temp for the water in the tank uses more energy.

I'd shoot for 140˚ water out of the tap. Insulate the hot header pipe if you have a cold drafty basement. If 140˚ is not enough to keep up with demand, nudge it up a notch.

You're on well water, I bet. A constant 57˚ cold temperature.

The federal government in all its wisdom has the manufacturers set the default setting on water heaters at 120 degrees...
I agree that an on demand gas instant water heater is the most efficient (Navian is the best then Rennai).

I have ours set at 125 because it is a longer run that requires me to stand in the shower longer than I want to waiting for the water to come up to temps.

Paul,if your situation allows for it, consider getting some of that pipe insulation and wrapping as much of the hot water line(s) as possible. It really helps and is relatively cheap.

I vote for Other;
When my wife & I can shower in Jan & have hot water the whole shower!

The one I put in in June I left factory settings.
The one before that I jacked up the setting and it lasted twelve years before pop off valve went wonkey. I just replaced the heater .I guessed it was on last leg.

I have mine (standard electric tank fed from well) set at 145 top and bottom.

It was at 120 when we moved in, but wouldn't last for 3 showers (and the wife could shower with the tap on full hot). After bumping it up, I noticed the daily spike was lower in the electrical monitor from CMP. Not huge, but surprising to me nonetheless.

I figure that because the water is hotter, we spend less time trying to warm up, ultimately taking shorter showers.

It's only been a bit over a month, so no actual statistics to compare yet, but so far I'm not seeing anything to make me regret bumping it up.

 
Our water heater has no degree markings on the dial, just Warm at one end and Hot at the other. In the middle is a raised mark that I assume is the factory recommended setting. Probably 120 degrees based on other comments. We keep it set there, in the middle.
 
The main issue for us is the water heater is in the garage and the two showers are at the other end of a long house. It takes time to get hot water to the showers, no matter the temp setting. We just turn the shower on ahead of time and then finish undressing, brushing teeth, futzing around for a few minutes and by then we have hot shower water. We solved the capacity issue by going with a 60 gallon water heater. That provides enough hot water for both of us to take long hot showers.

120 degrees is the code requirement for commercial hot water, so as to not grow legionella. The bacteria that causes legionnaires disease.

Mine is set so 120 degrees is delivered at the tap.

It's a little hot, if I had small children I might dial back.

The lowest setting that meets your needs is the most efficient. The hotter it is the more you will loose.

I have mine on a mechanical timer.
50 gal, on in morning and night - about 10 hours a day.
Only two of us so it works well except on laundry days which I can manually flip.
Temp is set at normal temps.