Recently, we started to have hot water issues when one more than one person has taken a shower. The water temperature is goes from lukewarm to cold. I do have a insulation blanket surrounding the water heater. The water heater is about twenty years old. Is it possible that the water heater is starting die out? I have moved the temperature dial on the water heater to almost "hot" instead of being in the middle. This didn't resolve it.

Most likley one of the two elements has burned out. That or a thermostat is not working. Both can be troubleshot with ease.

However, if it turns out to be an element, be prepared for trouble if the inside of the tank is rusted real bad.

I had this happen on a tank about that old, it was a bolt in element. When I pulled out the old element, a small piece of the flange of the tank came with it.

Long story short, it leaked really bad, and there was no fix shy of replacing the water heater.

If you take one or more showers in succession that you will most likely run out of hot water. Let's do the math together:

You have 40gln hot water heater. Also, you have 4GPM shower head. You mix hot/cold water 3:1 ration. So, it takes about 12.5 minutes to complety deplete hot water. Of course, the closer you get to that timeline, the warmer the water will be, since new, cold water is entering your heater. Depending on the heater, it may take 30-45minutes to reheat new tank. Moreover, the colder it gets outside, the more rapidly your hot water cools down.

If you take one or more showers in succession that you will most likely run out of hot water. Let's do the math together:

You have 40gln hot water heater. Also, you have 4GPM shower head. You mix hot/cold water 3:1 ration. So, it takes about 12.5 minutes to complety deplete hot water. Of course, the closer you get to that timeline, the warmer the water will be, since new, cold water is entering your heater. Depending on the heater, it may take 30-45minutes to reheat new tank. Moreover, the colder it gets outside, the more rapidly your hot water cools down.

This makes sense too, however I'm noticing he uses the word "recently". Which tells me that something has changed.

Granted, someone in the household could be just taking longer showers. I can understand this in the winter time, when peope like to stay in the hot shower longer.

If everything checks out good with the elements and what not, might I suggest a "penny pincher" shower head. I have used them in my shower for years because of our low water pressure. It turns what seems like a trickle of water into a steady shower. It's max flow is 2 GPM, and you can adjust it for lower.

They sell them at walmart and other fine hardware outlets.

It's also known as "THE INCREDIBLE HEAD"

The "DO IT BEST" brand is known as the "PENNY PINCHER HEAD" because it uses so little water.

This version even has a little button you can press to shut off the flow while you lather up if you really want to conserve hot water...

Agree with you Andrew. I was going to give you positive feedback but the system didn't allow me to do so. So...

Yes, part of the solution is installing Low Flow Shower head, like the one offered in previous post, that uses little water. In my area it is the Code. But some people still remove flow restrictor to get more volume from their shower head creating exactly same problem the poster is experiencing.

ALDIYguy...

You said, "I have moved the temperature dial on the water heater to almost "hot" instead of being in the middle"...

Does this mean that you have a GAS WATER HEATER? What size gas water heater?

Get back to us and we can see what next step is. Could be a dip tube has gone bad, or the gas valve (thermostat) or gas burner has gone bad. These are not usually worth repairing on a 20 YO water heater... ;)

Let us know more here...

Thanks... MARK

Aldiy...

I see that you posted an agree rating on my answer indicating that you have a GAS water heater (thanks... :)). Gas water heaters do not have elements... ok?

Post the response you started to post as 1/2 got cut off and I am unclear what exactly is going on. Also, confirm the size of the water heater...40, 50 gallon, etc..?

Thanks...

There is no "heating element" on gas heater.

It may be malfunctioning thermostat of most likely result of cold weather.