Wasting electricity?

[corbintech]

Hello,

I have something bugging me.

Six seconds after my wife gets in the shower my element kicks on. Water is entering the water heater at a rate that the element cannot keep up with.

I have been driving myself crazy over this. There are six people in my home and every time one of these people step into the shower a 3500 watt element on my heater is spinning my power meter all while doing really nothing at all until the water is turned off.

I was wondering why something like a flow sensor is not available. When the rate of lose hits a certain point the element would not kick on until the rate was off or at a point that the heater could keep up.

Is there anything like this?

Thanks in advance.

If nothing like this is available, feel free to make it and I will gladly buy one. This really has been bugging me.

 

[Mr_David]

you can install a flow switch on the inlet side of the water heater if that is what you want to do. All on demand / tankless WH have a flow switch to prevent heater ( gas or electric ) from coming on unless there is water flow.

You could install a switch that prevents the element from coming on when there is water flow.

But that would mean every time some one turned on a faucet it would interrupt the current flow through the element.
You watch a toaster toast your toast? Or an electric stove heat up.
It's not like switching on a light bulb.
Takes time for a heating element to reach it's maximum heating potential.

Your right, the water heater element can't heat the water faster than it is flowing through the heater but it is still heating it.
As the cold water comes into the heater at the bottom, the hot water rises to the top. If the element is off during this process the cold water remains just as cold as it was when it entered the tank. Then when the flow stops and the element kicks on it will just take longer to heat the water.
If the element is on when you have flow the water starts to heat immediately.
So you really are not wasting the electricity. you might even get just a bit more shower time in if the system is left the way it is. They slightly heated water mixing with the hot water versus the colder water mixing with the hot as it rises to the top and out of the heater.

Does that make scence ??

Flow switches @ Grainger

 

[corbintech]

I understand what you are saying.

My heater has a recovery rate of about 18 GPH. I have the heater set at about 130 degrees (never really exact). If someone takes a 15 minute shower averaging about 10 gallons, in that 15 minutes with the rate of recovery, I would have used the equivalent of two full size microwaves running for the full time while maybe raising the temp of about 1 gallon to decent temps.

My heater never has run out of hot water ever with 2 people showering back to back. The high(ish) temp allows us to use less hot water while in the shower. I just don't know if the return is worth the investment. My meter spins fastish while the element is on.

I have also thought about having a timer installed. I would have to look into the rate of lose (I wouldn't think it is that high, I keep my indoor temp at 74 in the summer). I would like to set a timer (if I go this route) at a 7-10 degree lose then kick on perhaps. This is my first time ever thinking about these things and I am trying to save a little money.

Thanks for the reply.

 

[phishfood]

You aren't going to save any money.

The element is activated by a thermostat, which turns on when the water temperature in that area of the tank drops below it's set temperature, and it shuts back off when it gets back to the set temperature.

Say a shower uses 20 gallons of hot water. And say you have 70 degree incoming water and are heating it to 130 degrees.

It matters none whatsoever if the element starts heating the 20 gallons of water as soon as the shower turns on, or if it waits until the shower is turned off to start heating. It will take the same amount of electricity to raise 20 gallons of water 60 degrees either way.

Start heating as soon as the shower turns on, it will shut off sooner. Wait until the shower is turned off, it will shut off later. But the same amount of energy will be used.

 

[Mr_David]

Start heating as soon as the shower turns on, it will shut off sooner. Wait until the shower is turned off, it will shut off later. But the same amount of energy will be used.

Nicely said. Kind of what I was trying to say, You just said it better.