So for the past few years, I would keep the thero at 68 during the day
while I am at work, then to 70 when I am home.
With the increase in oil cost and more inefficiency in my heating
system (I am working on it), I am needing to put the thermo to 72
degrees when I am home to be comfortable.
Here is a formula:
10 hours @ 68 degrees = 680
14 hours @ 70 degrees = 980
Total of hours x degrees = 1660
10 hours @ 65 degrees = 650
14 hours @ 72 degrees = 1008
Total of hours x degrees = 1658
Does heat work that way, or does it take more juice to get to 72
degrees instead of 70?
Feel free to tell my how foolish my heat calculation is.
Your looking at it in the right direction, but your method of
calculation isn't correct.
The first thing to realize is that heat always runs "downhill" from hot
materials to cold ones. and the way to look at it is that the amount of
"juice" as you put it, is basically delta-T (the difference in inside
and outsided temperatures) times a factor for whatever "thermal
resistance" the heat flows through, in your case, that's the insulation
of the walls, roof and windows of your dwelling. Winds outside come into
it too, as a second order effect.
And yes, all other things being equal it does take "more juice" the get
to 72 than to 70, and more to keep it at 72 than at 70, when the outside
temperature is below 70.
The simplest and most efficient way to do what you are talking about is
to set the heat as low as you can when you're not home, as long as you
don't run into the possibility of freezing plumbing, and then turn it up
to 72 or whatever you want when you return. That's providing you don't
mind whatever waiting time your heating system takes to raise the
temperature to where you get comfortable. If you can't tolerate the
wait, then set your "not home" temperature a little higher.
You might also want to consider going a little higher tech and using a
timed thermostat set to raise the temperature a bit before your expected
return, or use some of the whiz-bang gadgetry that lets you control
stuff like that with a telephone call.
Thanks to Jeff for the detailed explanation...I will look to a
prgrammable thermo -
Scott, my system is inefficient because one of my big radiators is not
getting too hot. I think its a valve issue, so to get the house
confortable, It has to go to 72.
48 degrees !!
I have a 18 year old cat in the house - don't want a catcicle when I
get home. Maybe I will drop it to 62 and see how that goes.
We drop it to 45 and our cat Darwin hasn't said he minds it at all. I'm
hoping it'll help burn some of the fat off of him.
He's gotten so rotund that he can't run as fast as the mice anymore, so
he's mechanized the process:
We're in the Boston area BTW. Wuz 14 F outside when I left this morning.
I just remembered I should have mentioned that if getting a timed
thermostat and installing it is too big a hassle you can jury rig one
Just get an inexpensive plug-in-the wall light timer and connect a small
lamp bulb, like a nightlite bulb, to it on a length of cord.
Let the timer light the bulb when you want the temperature to be lower.
Experiment with locating that bulb on the wall below the thermostat.
You'll find a location where the rising heat from the bulb will "fool"
the thermostat into thinking the room temperature is higher than it
really is and thus "push the heat down" the amount you want.
A "red-neck" solution, but one which works quite well.
Now that is some ghetto thermo rigging...but it makes me wonder - the
xmas tree is within a few feet of the thermo - perhaps that is making
the house cold at night when the tree is lit..
Well, X10 makes a "thermostat setback" gadget which works on the same
principle I described, nly it has an adjustable power level so you don't
have to move it up and down on the wall to adjust the number of degrees
of setback. Here's one now:
And, back in the '50s when I worked for a TV shop, those big vacuum tube
TV consoles put out a lot of heat. When we were delivering one to a
customer's home and they told us to put it against a wall right below
the thermostat we knew enough to warn them that the heat from the TV set
when it was on would fool the thermostat and make the room "get colder".
Put a heating pad on the bottom of the cat house. Small electric charge vs.
big heat bill. Also when you go to sleep turn the heat down and use an
electric blanket. Have your programmable thermostat fire up the heat a half
an hour before you get up.
About the time I had mastered getting the toothpaste back in the tube, then
Setting the thermostat and actual temperature are different things. Why do
you have to set it higher to feel the same? The thermostat is a switch. The
heater is either off or on. If it is running and brings the heat high
enough to trip the switch, that is what counts. Other factors are at work
here. It may be easier to fix that problem.
Yes, you have the right idea. That is similar to the "degree days" the oil
companies use to determine when to deliver to you. IIRC, they use the
differential between actual temperature and 60 degrees.
You have to think about temperature differential. The greater the
differential, the greater the loss.
You can increase comfort by adding a humidifier, cutting down drafts that
create heat loss, add insulation. If it has been a long time since you've
done any of that, do a quick review to see if there have been any changes.
Now, this is an interesting subject. First, the actual temp isn't really 68
or 72, cause the actual zero is about -450, where the mollecules stop
Your furnace runs just enough to replace the heat that is lost to the
outside. If you lose some ammount of heat, the furnace replace it.
Heat loss depends on a couple things. Air loss (drafts) and conduction
through the walls, ceiling, etc.
If it's colder outside, the air leaking in is colder. And the delta T
(difference in temperatures from inside to outside) is higher.
Anyhow, if you turn your thermostat down it saves you money. Because the
delta T is lower. And also the air that leaks out isn't quite as hot (and
you didn't pay to heat it up hotter).
If you don't feel warm enough during the winter, get a humidifier.
Christopher A. Young
Keep Jesus Christ in CHRISTmas
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