# Turn thermostat down or leave steady?

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• posted on October 30, 2009, 1:30 pm

On Oct 30, 8:24 am, Jules . Anything with a lot of inertia, like slab heat, is best left alone

Does that necessarily follow? Anything with a lot of inertia will cool off much more slowly too. So you don't have nearly as far to recover when you raise the temp again.
Maybe that part of the question should be rephrased as a time constant.
Drop the temperature by 10 degrees. There will be a transient period while the temperature is falling. Then there will be a steady state period while the lower temperature is maintained. And another transient period while the upper temperature is reestablished.
Clearly energy use is lower during the first transient period, as in zero.
Clearly energy use is lower during the steady state period due to the lower temperature setting.
Not so clearly energy use is higher during the second transient period, your heat will not cycle until the new steady state is reached.
If lower steady state is never reached because the setback is for too short a time, then it seems logical that energy use during transient periods would average to 50% duty cycle. But this isn't necessarily true, because the time periods may not be equal. Loss of heat to the environment is not at the same rate as gain of heat from the furnace.
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• posted on October 31, 2009, 2:04 pm
There's a factor you haven't considered.
If you have a programmable thermostat it doesn't apply.
But if you have a manual one, changing the setting frequently will make it wear out faster.
Never having worn one out myself, I don't have a guess at how much faster that would be.
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• posted on October 30, 2009, 12:24 pm
Next week, I'll ask how to hang the roll of toilet paper. Or how to change a light bulb.
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Christopher A. Young
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• posted on October 30, 2009, 3:01 pm
On Oct 30, 7:24 am, "Stormin Mormon"

TP must unroll from the topside of the roll (so loose end hangs away from the wall). This way pulling the paper up lessens the friction imposed between the roll core and the dispenser hub allowing less- restrictive unrolling. Additionally having the paper hang away from wall, lessens the occurence of fingerprints (and finger nail scratches) on the wall itself caused by people scratching against said wall to find the roll end. Additionally there is better visibility of the roll top as opposed to the roll bottom in finding the paper end in a visual manner (as opposed to a "by feel" manner).
This is a well-known fact, TP must unroll from the top of the roll, not the underside.
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• posted on October 30, 2009, 4:35 pm

Let's drop this and start a new topic if TP is your prime worrry!
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• posted on October 30, 2009, 9:47 pm

BTW, which way does the ground go on a duplex outlet, up or down?
:-)
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• posted on October 31, 2009, 1:26 am
wrote:

The ground is supposed to be pointed toward the grave of Nikola Tesla, or at least as close as you can get.
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• posted on October 31, 2009, 1:34 am
Is that like Muslims praying toward Mecca? Need a big pointer in every town square?
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Christopher A. Young
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• posted on October 31, 2009, 1:31 am
The ground is always on the top. Cause if a piece of wire or metal drops behind the plug, the ground keeps it from shorting the two flat prongs.
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Christopher A. Young
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• posted on October 31, 2009, 2:05 am

Yea but if the ground is on top and orange juice spills in it, the ground will divide the water left and right just beyond the prongs (regardless of liquid volume, velocity, viscosity, wind, gravity, sunspots, etc) and effectively nothing happens. Ask MacGruber.
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• posted on October 30, 2009, 9:56 am
Stormin Mormon wrote:

Six of one, half dozen of the other. Depends on how long you are gone. Leaving the thermostat at a steady temperature saves energy. On the other hand, a lower difference between the inside wall and the outside wall means lower heat loss. So lowering the thermostat does save energy in the long run. Now, constantly raising and lowering the temperature for short periods wastes energy. When you raise it you have to reheat not only the heating system but the entire inside wall, floor and ceiling not to mention all the furniture and appliances. When you lower the thermostat, all those items lose all their heat again the heat is drawn out into the room and the room loses it through the walls to the outside. So....use your little noggin.
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• posted on October 30, 2009, 12:20 am
Still, it's less energy used cause less energy is lost.
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Christopher A. Young
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• posted on October 30, 2009, 12:28 am
On Fri, 30 Oct 2009 05:56:01 -0400, Van Chocstraw

So if you are gone a long time it's six, and if gone a short time, it's half a dozen?

ARen't you thinking of gas mileage?

I will. All the extra things you mention, walls etc. are included every step of the way. So it saves money to turn down the heat.
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• posted on October 30, 2009, 3:17 am
mm wrote:

Nope. If you lower the thermostat, gone for an hour, takes an hour to cool off the house, then come home and turn it back up it takes twice as much energy to heat up the house and all the contents than if you had left it alone. Put that in your pipe and smoke it. Now if you go to Florida for 3 months and turn it down to 50 degrees, yes you save a bunch.
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• posted on October 30, 2009, 4:23 am
Van Chocstraw wrote:

Hmmm, What kinda dummy is set the 'stat back when going for an hour. We're talking about typical situation, all day or all night set back. Be reasonable. Dig out a research test result done by such as Honeywell and utility outfits. Saving energy is proven thing no matter what. Also no matter what, insulating house well is pre-requisite for things like programmable 'stat. Your argument does not have legs to stand on. Forget it.
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• posted on October 30, 2009, 12:23 pm
I don't have a pipe, and that nonsense wouldn't light, in any case.
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Christopher A. Young
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• posted on October 31, 2009, 12:18 am
On Thu, 29 Oct 2009 23:17:03 -0400, Van Chocstraw

Whether it's an hour or a month will determine how much money you save when you turn the furnace down. If it is only an hour you might save only a penny for all I know, but you won't use as much energy.

No. You just made that up and it's nonsense. It takes less, not twice as much.

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• posted on October 30, 2009, 1:53 am
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wrong...too much work to convince / educate you
cheers Bob
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• posted on October 30, 2009, 2:07 am
Van Chocstraw wrote:

Wow, Where are you coming from? The lower the setting the longer the setting. You save energy. I am talking about how much saving. Just it saves. Our 'stat is set to 17C from midnight. Back up to 20C at 7 in the morning. It does make a difference. Now our NG price is 3.80 per GigaJoule. Electricity is 7 cents/KWh
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• posted on October 30, 2009, 12:29 pm
Well, sad to hear that you live in an over regulated part of the world.
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Christopher A. Young