# Turn down water heater during the day?



## G Dot (Dec 3, 2008)

Is this worth doing to turn it down to WARM while at work?  

Then come home and turn it up?  Or does this technique use more gas to heat it back up?  Thanks for your help.

Glenn


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## woodchuck (Dec 3, 2008)

With a well insulated tank and pipes it probably wouldn't come on but once or twice during that time anyway. I would say it would be a waste of time for just a few hours.


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## glennjanie (Dec 4, 2008)

Hello Glenn:
If you pass right by the water heater on your way out and back in, it would be worth your time to turn the knob. Your gas water heater will pick up the temperature very quickly. I personally prefer the 'on demand' water heaters but they are considerably more expensive. 
We have a geo-thermal heat pump that heats our water so we simply have to store it. Of course there are days the heat pump doesn't run very much and the electric water heater keeps it warm for us. I have the water heater thermostat set 10* below what the heat pump will provide so we only use the electric elements when necessary.
Glenn


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## GreenIsGood (Feb 16, 2009)

We don't turn our's off - but we turn it down to pilot-light only setting during the day. That seems to keep it at a more economical 'heat temperature.' What I mean is, I can still wash my hands and do the dishes, but I wouldn't take a shower or bath at that setting. When we are ready to bathe, we simply turn the water heater up - giving it about 30 minutes notice. That's it - a hot shower!

Plus, my tank is covered with a thick insulated blanket - this totally saves energy/money. 

Leaving it on all day seems like a waste of money to me.


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## racsan (Mar 21, 2009)

but if its maintaing a constant 120-130 isnt that more effeicent than heating up a tankfull from complete cold?  seems like if the a/c is set at a constant setting in the summer the power useage isnt bad, but if it keeps getting turned on the off based on when the house is occupied then more electricity is used. now if you were going to be away for a week or more, sure. but on a daily basis i think it would end up costing more to keep turning it down & back up.


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## nma (Aug 19, 2010)

racsan said:


> but if its maintaing a constant 120-130 isnt that more effeicent than heating up a tankfull from complete cold?  seems like if the a/c is set at a constant setting in the summer the power useage isnt bad, but if it keeps getting turned on the off based on when the house is occupied then more electricity is used. now if you were going to be away for a week or more, sure. but on a daily basis i think it would end up costing more to keep turning it down & back up.



No. Maintaining a temperature over a period of time is always going to be more expensive than just heating it up when you need it. Having said that, I'm doubtful that this is going to save a lot of energy - it will save some though.


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## mudmixer (Aug 19, 2010)

It just makes the person feel "GREEN". but the savings would be negligible. 

Spend the time and effort and just plant trees that will not be removed since they are supposedly a recycled material, except some countries frown on using wood for construction and there are better agricultural uses for the land that is precious in some large countries.


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## nma (Aug 19, 2010)

It's possible a thermostat might be worthwhile if your water heater is really old and poorly insulated, but modern ones it really probably isn't worth it.


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## Nestor_Kelebay (Aug 20, 2010)

racsan said:


> but if its maintaing a constant 120-130 isnt that more effeicent than heating up a tankfull from complete cold?  seems like if the a/c is set at a constant setting in the summer the power useage isnt bad, but if it keeps getting turned on the off based on when the house is occupied then more electricity is used. now if you were going to be away for a week or more, sure. but on a daily basis i think it would end up costing more to keep turning it down & back up.



This can be an easy problem to trip over if you're not careful in how you analyze it.

Basically, turning down a water heater's temperature during the day works to save money for exactly the same reason that timed thermostats save money by turning down your house's temperature at night.

The reason is that adding heat to your water or your house is an investment, no different than putting in new appliances or building a deck.  So, if it weren't for heat loss through the insulation, you'd pay to heat your house once in October and then enjoy comfortable indoor temperatures for the rest of the winter, just as you enjoy new appliances or a deck to have bar-b-ques on for a long time after making the investment.

Unfortunately, that's not how it works.  What you're actually paying for on your gas or electricity bill is not the heat you put in, but the heat you lose.  You burn gas or use electricity to replace heat lost through the insulation.

And, it stands to reason that you simply lose LESS heat by having a lower temperature differential across the insulation.

In fact, even when you're water heater is heating the water back up in the late afternoon, or your house is warming back up in the morning, you're still saving money during this re-heating period because the rate of heat loss from the water heater or house is still lower during the reheating period than it would have been had you maintained a higher temperature differential throughout the day or night.

So, even though the gas or electric meter is running, the net effect is a savings in energy because you're replacing LESS heat than you otherwise would have if you'd maintained a constant temperature.  

Certainly the potential savings would be lower by turning down a water heater during the day than it would for letting a house cool down at night, but that's because there is much greater heat loss through he exterior walls and roof of a house than there is from a water heater.  Still, the savings would be proportionate to the amount of heat loss.

One way to REALLY save money is to turn the thermostat in your house down, and put on a sweater.  Or, wear LONG underwear; both long sleeved undershirts and long johns.  You do that, and you'll be surprised at how much you can save on your heating bills.

No lie.  I've had tenants ask me to come to their suite in the winter to check the thermostat and zone valve because they're cold.  They're in their suite wearing nothing but shorts.  No shirt, no shoes, not even socks.  They'd be butt naked except for the shorts.  And it's 35 degrees below zero outside.  It's no wonder they feel cold.  Great grampa would hang his head in shame.


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## Perry525 (Aug 22, 2010)

As you can see, there is no way to stop heat moving to cold.
You can merely slow its escape.
If you have 6 inches or more of polystyrene insulating your heater, there will still be a loss via the water in the connecting pipes.
Water is a very good conductor of heat, in fact it is 4,000 times better than dry air. You will loose heat.
However, the amount of heat lost is relevent to the temperature difference between the water temperature and the outside air or room temperature.
For a lot of the year it will be so small that you cannot measure it.


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## carnuck (Oct 7, 2010)

My tank is being rigged into a timer that furnaces use. (it's electric, but gas should do that as well) Just figure how often you need the water and what time of day then program it to come on a couple hours before that. 
   I'm putting one of those mini tanks for the sink in the kitchen (220 volt is more efficient than 110 because the other "half" of the sine wave is wasted since the meter reads the flow down either leg as both sides being used, which is why you want a "balanced" fuse box )
   This will cut down on the energy used as well as amount of water (it won't have to run 15 minutes just to get warmed up enough for a sink of dishes)

If you don't have one already, invest is a check valve for your water tank inlet. It will keep the hot water from flowing back out of the tank when the cold tap is turned on (due to pressure drop) and also insulate it from transferring heat to the cold water in the pipe (the flap is usually rubber)
   I've been thinking about adding an iPhone app so that I can turn the hot water on or off for like a couple days when I go somewhere, or turn it on at my cabin (once I get the well, septic, electric, plumbing, etc done) before I go out there.
   Also for the Luddites in the family, I can rig up an "easy" button to push and turn the tank on manually as the cabin tank will be on LPG with low voltage control (I already have simple LED lights running off a truck battery and small solar panel)


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## havasu (Oct 7, 2010)

My recommendation is if you want to go green, check out the latest tankless water heaters. I installed mine last December and so far this year, my natural gas bill has been reduced 40%. I have a recirc system, with a timer, so I have hot water on demand both in the AM when I take my shower, and in the PM when I wash up before jumping into bed. The entire system cost $1500, but with the 30% tax rebate, along with the savings of $22 per month on my natural gas bill, it's getting cheaper to run than a conventional tanked water heater. It also mounts tightly to the wall, takes much less space, and is 95% energy return.


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## mudmixer (Oct 7, 2010)

In the cooler months, the heat is really not lost because it reduces the heating load on a furnace minutely. Even in a cooling mode, pulling down a shade would do more good that cutting the temperature down on a tank since it may not cool off enough to come on before you turn it back up.

Our gas for hot water (inefficient model) is less than the monthly connection charge and taxes required, so I don't really worry, but if I want to feel really "GREEN", I could turn it down when I go to the store and them think I am accomplishing something even if it is a waste of time.

Dick


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## Perry525 (Oct 22, 2010)

jammydoug said:


> Hi
> Our water heater flooded our garage. I am assuming it needs replacing. I shut off the water to the house and the pilot on the water heater, but how do I shut off the water going to the water heater? What is the typical cost to replace a water heater?



First of all find out where the water is coming from, a loose joint perhaps?
There will be a valve under the heater to turn the water off.
Then consider if you can repair it by tightening the joint, or by replacing the part or parts.
Only if it is beyond repair, buy a new one.


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## Redwood (Oct 22, 2010)

Perry525 said:


> First of all find out where the water is coming from, a loose joint perhaps?
> There will be a valve under the heater to turn the water off.
> Then consider if you can repair it by tightening the joint, or by replacing the part or parts.
> Only if it is beyond repair, buy a new one.



Perry considering where Jammydoug is from and that he is just here to drop a spam link. I wouldn't worry to much about a water heater as we know it...:rofl:


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## ilikeblue (Jan 26, 2012)

I've always heard no, because it wastes energy having to bump itself back up or down to whatever you would have it when you were in the house.


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## paul52446m (Jan 26, 2012)

Every one here is talking about the heat loss through the insulation on the heater.
 On your standard water heaters , you have a 3" tube going from the burner up through the 
 water heater to the stack, so the hotter the water the faster the air flow up through this tube. and that heat loss up the stack to the out side is a lot more then the loss through the insulation. So turn it down will slow down this heat loss.  Paul


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## carnuck (Feb 2, 2012)

There is a bi-metal coil "flap" that can be fitted inside the "chimney" of the water heater pipe that opens at over 100 degrees then closes around 75 to keep heat in.


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## paul52446m (Feb 2, 2012)

carnuck said:


> There is a bi-metal coil "flap" that can be fitted inside the "chimney" of the water heater pipe that opens at over 100 degrees then closes around 75 to keep heat in.



They are called a bi-metal  stack damper. You have to watch where you use them. When the heater comes on it will take a min. for it to open and in that min. you will be dumping burned gas fumes in the area around the heater. I don't know if they still use them or not. Because the carbon monoxide tester we use in homes today are very sensitive, so it could set them off.   Paul


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