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Please help settle an arguement!


My friend and I had a heated argument (no pun intended) the other day in reference to heating one's home and cost savings. He cannot see why lowering you heat (not just at night) from 68 to 64 saves any costs. His arguement is that once you bring your house to the intial heat level (68 or 64) that the furnace will kick on when the house temp drop one or two degrees, therefor, whether the thermostat is set at either temp the furnace is only heating the house one or two degrees.
I argueed why not set it at 80 degrees then. His agruement should hold no matter what the house temp is set at. I gave this example. The outside temp is 30 degrees and your trying to maintain a inside temp of 68 degrees, you are trying to keep the house 38 degrees above the outside temp. Keeping the termostat set at 64 the furnace will kick on for the same amount of time to heat the house one or two degrees, but it wont happen as often and through out the heasting season this adds up to SAVINGS.

He disagrees. Please help me settle the arguement. This guy wants scientific proof. I could not find any on the web. If there is a web site I can use please let me know. I will use any reply to prove my side.

Thank you


Re: Please help settle an arguement!
Re: Please help settle an arguement!

Heat Transfer Rate is based on the squre of the differences in temparatures of two areas multiplied by the coefficient of heat transfer between the two area.

For example, you home is area 1, outside is area 2. The Coeficient of heat transfer would be based on how well your home is insulated, caulked, etc. Regardless, this would be constant until you change the amount of insulation, do repairs or over long period of time see changes in your structure. Call this the "R" value.

If temperature outside is the same say 25F (T1) and you set the temperature inside to 60F (T2) the transfer rate is = (T2 - T1)squared * R, = 1225R

Now you Crank up the heat inside to 68F, your new T2. Assuming the temperature outside is still 25, and you have not changed your R value, the new transfer rate is 1849R.

Moral: The rate at which you lose heat from your house to the environment is propotional to the square of the temperature difference, and is linnear proportional to how well your home is insulated.


Re: Please help settle an arguement!

Any amount of temperature set-back (either done manually or through a programmable thermostat) will result in energy savings because the less the temperature difference between the indoors and the outdoors, the less the heat loss.

The longer the set-back time, and the greater the set-back temperature, the greater the resulting savings.

Furnaces do not work harder, but output heat at a constant temperature until the thermostat senses the target temperature.

The greater the difference between the actual temperature and the desired temperature, the longer the furnace will run, but it will be less than if it maintained the higher temperature all night long.

The less frequent the heating system operates the less fuel consumed and the less electricity used.

Links :


Re: Please help settle an arguement!

The Two Answers Are Correct But This Might Help. Every Home Has Air Changes Per Hour.the Air That Is In Your Home As You Are Reading This Won't Be By The Time You Are Done Answering This. While You Are Up And Using Your Home You Want It To Be Comfortable While At Work Or In Bed You Do Not Need It At 68. Remember Your Home Changes Air Every Hour So Why Heat The Neighbors Yard When Not At Home. This Is A Simple Example, But So Am I.

Re: Please help settle an arguement!

Here is simple science--Tell Him to wear a jacket inside for a month at 64 degrees then see if your bill is lower.When you prove it tell him to leave his coat off the rest of the winter..
Merry Christmas

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