First what fuel are you using? Do you have an time of day demand meter?
Can you and yours stand the temp swings?
Longer times off and larger temp differences, mean it takes longer to get
back to the set point.
Here in Az the utilities say " more than 5 degrees for more than 8 hours
saves more than 10%. However there is an limit to this and doubling the
temp and time will not necessary mean double the savings.
Who knows what to believe, but everything I've read says the main reason for
NOT setting such wide temps swings is that it'll produce extra wear on a few
of the furnace's parts. The instructions that came with my thermostat said
4-7 degrees. I tried 10 in the beginning, but the heat ran so long in the
morning that it was stifling in the house. The potted plants were wheezing.
One thing I *have* observed is that your sense of warmth is as much related
to the objects you touch as it is to the temperature of the air. Some years
back, we had an ice storm here which killed power for a week. Once we had
heat again, it took almost 3 days for the objects in the house to warm up
again. Everything we touched made us feel cold, and this was in a heavily
insulated house. Meanwhile, the thermostat cycled normally, saying it was 68
or 70 or whatever we'd set it for.
Anyway....a 25 degree margin doesn't sound right.
Often people will say that this floor is cooler than that floor. Yes, it
may feel that way but no, it is the same temperature. It is all about heat
A wood or ceramic floor will FEEL cooler than a carpeted floor. Why?
Because your body is 98 degrees, the floor is about 70 degrees. Heat is
always trying to transfer to the cooler spots. When you step on carpet, you
are suspended by a network if fibers and plenty of air gaps for insulation.
When you step on a wood floor, you have more contact with your skin and more
heat is being pulled from your body. Ceramic will pull the heat faster than
wood or vinyl.
One more thing since we are discussing heat and comfort. Turning up the
thermostat to a higher setting is not going to heat the room any faster. The
burner is either on, putting out as much heat as it can, or off, putting out
no heat. Cranking up the dial won't make the burner fire any hotter.
I used to be the first in the office where I worked and turned the heat on.
Then one of the ladies would com in, turn up the thermostat. Then another
would come in and turn it up more, then a third would to the same. I'd go
turn it to th e normal setting and they jump all over me because they
suddenly felt cold even though the heat was still running the same way.
I'm all for equality, but there is something seriously wrong with the way wo
men control heating systems. My ex wife *and* he woman I'm seeing now both
do the same thing if it's too hot or cold in the car: They turn off the
whole system. They only seem to be aware of the fan control, and it's
useless trying to explain that other funny knob. "Ya know....it doesn't have
to be off or on. You can adjust the temp control somewhere in between...."
No reaction. Vacant stare.
Years ago, when I worked in a large office, the women were forever turning
the temp up and down, all day long. The boss finally put a locked box over
the thermostat, set it for 68, and suggested sweaters. We came close to
having an armed uprising, but they got over it.
They turned it DOWN??? A woman actually turned it down? Must have been
about 50 and had hot flashes.
One woman was always looking at a little thermometer she had on her desk.
If it said 70, she turned up the heat. One day when she went to lunch, we
pushed the glass up a little so it read about 3 degrees higher. Problem
it is an absolute biological fact. women have a temperature range of about
0.2 degrees where they are comfortable. go above that and they turn on the
ac. go below that and they turn on the heater. what makes it worse is that
not all women have the same baseline temperature, but all only allow for .2
degree swings. get the wrong two women in a room together and blood will be
If I remember, this question was about the "setback" when programming
a thermostat. The question was quickly, or originally confused with the
"differential setting" of a programmable thermostat.
No one has pointed out that some (at least one that I know about) have
a "differential setting" that can be programmed. That value is
nominally set to "10" on the stats I've programmed, and the value is,
I think, 10x the on/off degree difference for the system. This is
sometimes called an anticipator setting, I think.
The 10 "degree setting" that the original writer heard about on a
radio show (or somewhere) for the "differential" has NOTHING to do with
how low a thermostat should be setback.
Perhaps someone who has access to the original posting can check this
out, since I am not an expert in heating systems. Because of this,
I have been waiting for an expert to comment; since that does not seem
to be happening, I'll take a chance that my understanding of the
"differential" setting on a programmable thermostat is correct. --Phil
Phil Munro Dept of Electrical & Computer Engin
mailto: firstname.lastname@example.org Youngstown State University
Good point...These are the settings I use
normal setback 10 degrees
Differential on programmable stats (single stage gas/electric)normal 1.0 to
Differential on mechanical stats (single stage gas/electric) 2 - 5 degrees
heat pumps and 2 stage will normally be 1 - 2 degrees differential on the
first stage with the second stage being 3 - 5 degrees below the set point.
Other folks may use different settings...your milage may vary.
Now, you have to factor in personalities. I'm happy sleeping in a tent at 35
degrees, with a serious sleeping bag. At home I'd be happy with the house at
50, since I have a down comforter that was apparently designed for the
My significant other - she's a different story. She thinks the comforter is
too warm. But, she bases this opinion on how it feels when we first get in
bed. At that time, the house hasn't cooled down yet. I could outline my plan
for dealing with this, but as we've already established earlier in the
discussion, there is no logic to how women perceive temperature.
When I install a programmable stat, I do the initial installer programming,
I don't mess with the factory default time/temp settings, and leave the
owners manual (not the installers instructions) with owner.... after that,
they are on their own. You can do what you want.
Suggest you limit your athletics to places other than under the
comforter. Prior to insertion between the sheets, remain above the
covers scantilly clad for several minutes of inactivity while herself
and everything else has a cooldown period. Once she feels a bit cold,
get into the cold bed. Now, because the body is a bit chilled, the bed
takes a few minutes before feeling warm and when it does, it is a
welcome sensation so the comforter doesn't feel like a nuisance.
Sometimes I'm hot right after I get into bed. Logically, I know that
I'll need all the covers later in the night and that it is not wise to
completely remove layers just because I'm feeling hot in the short
term. I find that I can flop the covers back from my chest and leave
just the sheet up to my neck, even without disturbing how the covers
lay on my wife. Sometimes I'll put one arm out above the covers as a
"radiator." The arm will then feel a little cool and help my body
perceive that it's cool, and keeping the hot arm away from the rest of
the body helps reduce the perception of "hot." A few minutes before or
after I doze off, my arm or chest will get cold and I'll flip the
covers back over my body, without even waking up if I've already gone
to the land of nod.
I believe it is the opposite for furnace run time and wear, most of your
wear is in turning on the furnace, in other words long cycles are better
for less wear on components. So the OP wont wear out components faster,
just the opposite.
For conventionally fueled systems (oil, natural gas) the longer you leave
the furnace off, the more you will save. All the "maximum setback" talk is
just noise, without any basis in scientific fact.
"Heating and Cooling Myths
A common misconception associated with thermostats is that a furnace works
harder than normal to warm the space back to a comfortable temperature after
the thermostat has been set back, resulting in little or no savings. This
misconception has been dispelled by years of research and numerous studies.
The fuel required to reheat a building to a comfortable temperature is
roughly equal to the fuel saved as the building drops to the lower
temperature. You save fuel between the time that the temperature stabilizes
at the lower level and the next time heat is needed. So, the longer your
house remains at the lower temperature, the more energy you save. "
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