# Gas Water Heater Question

• posted on May 9, 2007, 11:47 pm
I live alone in a small house, and I was wondering if there was any downside (particularly with regard to safety and the expense of using the heater) to turning off my gas heater at selected times during the day. I really only use the heater when I wash dishes and take a shower at night, and I am wondering if repeatedly turning off the heater everyday (late in the evening after I have used it) is safe and whether it will save me substantial amounts of money. Thanks for any assistance that anyone can provide.
JD
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<%-name%>
• posted on May 10, 2007, 12:04 am

Subjecting the heater to expansion and contraction for the heating cycles is not a good idea either and it is more prone to crack the liner inside. If you can, see how often the burner cycles and you can compute the gas used to maintain the temperature versus a long time to bring it up to temperature.
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<%-name%>
• posted on May 10, 2007, 1:09 am
wrote:

Would it use enough to show up on the gas meter?
Edwin's is the better way, but maybe you could turn off the water heater before you go away for a couple days, and without turning the gas back on, see how hot the water is when you get home. That will give you an idea of how much heat you are losing, and how much heat you would need to keep it warm. It might only be the first 30? seconds of water that is indicative, becasue as you use water, cold water enters the tank. I don't know how long it takes to mix with the hot water.
Also, don't forget that however much the water cools off in the night, you'll end up warming it back to the orginal temperature the next time you do dishes. So say the water is set to 140 degrees and in 18 hours it cools to 130**. But let's say 120. So the average temp over 18 hours would be in the middle, 130. If the room the water heater is in is 70 degrees, there would be a 60 degree differential instead of the 70 degree differential if the water were still 140 all the time.
**I don't think it will cool more than that. I went through involuntary testing with an electric wh. It would break and I'd see how long the hot water lasted. IT LASTED FOR 3 OR 4 DAYS!!!!! if I used very little. I was showering somewhere else, and pretty much just washing my hands, but still, it radiated so little heat that it was hot for 3 or 4 days. This was a 12-year electric water heater and they come iirc 3 inches of insulation. Can one use a water heater blanket on a gas wh. My wh had one when I bought the house, but when I replaced the wh, it was sort of messed up and for whatever reason I didn't buy another one.
So it will radiate heat into the room at 6/7ths of rate it normally does. There are two ways that heat is lost from the water heater, a) radiation and b) using the water and replacing it with cold water. What fraction is each depends on how much hot water you use, and to a small extent, what the temp is in the room the wh is in.
FWIW, if the wh is in a room that you heat, or right next to one, like a closet off of the kitchen, any heat that radiates from the WH will heat your apartment in the winter and save you money on whatever other method you are using. Of course when the AC is on, it will be the opposite. You'll waste a little money with heat radiating from the wh, and then waste it a second time running the AC. OTOH, you only use the AC what, 3 months a year? And when it is more than 70 in the room, the water heater will radiate less heat.
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<%-name%>
• posted on May 10, 2007, 12:45 am

I can't think of any problems with turning the thermostat knob from your comfort level to the vacation setting on a daily basis. Physically turning it off and on, as is shutdown and relight the pilot will cost you more in the long run IMO.
I'm not sure you will save enough to make it worth the hassle. All you will save is the "stand-by loss", the cost of keeping the water hot with no use. You might Google "stand-by loss" +"gas water heater" and see what you can learn.
Single person, hand washing dishes, one shower, you might do as well just lowering the temp setting as low as you can go and still have enough water for your needs.
Colbyt
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<%-name%>
• posted on May 10, 2007, 1:44 am

It's safe all right, but what a hassle! It won't save you any money, especially for all the time you'll spend going up & down the stairs.
Instead, buy a water heater blanket and if you're handy with plumbing, make a loop out of copper pipe to keep the heated water in the tank. Put it on the hot side of the tank. Heat rises, it can't sink, so the loop effectively stops the heat right at the highest point of the loop. This keeps all the hot water in the tank rather than migrating out of it and heating up all the associated pipes. (Those pipe insulation things are worthless, and furthermore, they're unnecessary with a proper heat trap.)
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<%-name%>
• posted on May 10, 2007, 3:11 am

Amazing new physics principle!
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<%-name%>
• posted on May 10, 2007, 3:23 am

But since almost no one has the proper heat trap that you recommend, they're not unnecessary for all those people, are they?
That leaves the statement that they are worthless, which others can comment on.
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<%-name%>
• posted on May 11, 2007, 1:10 am
wrote:

They are still worthless. For the cost of 3 feet of copper pipe, some elbows and about 1-2 hours' time, someone can build a heat trap and be done with the problem forever.