Stormin Mormon wrote:

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
jiggling.
Not really. It doesn't get down to absolute zero, at least in my
neighborhood.

You are concerned with the heat flow out of your house. Heat flow is
proportional to the DIFFERENCE in termperatures, inside and outside.
And it's inversely proportional to the R-factor of the walls.

In a previous house I wired an old electric alarm clock across the
circulator pump so I could measure how much the system was producing
heat for the house. The result was that only loose correlation with
the degree-days. Wind seemed to have a much bigger effect.