280, I have a question along the same lines here, regarding setback, etc.
We've got an approx 1800 sq ft house... it's an older house, built in 1969. We've got no exterior wall insulation except in the 400 sq ft addition (family room). Forced air gas heat, about 15 year old furnace (we think, based on maintenance stickers on the side of the thing....) The attic has some (maybe 6 inches, maybe a little less) blown cellulose insulation in the attic. No insulation in the crawlspace. Ducts are wrapped with insulation and foil... We recently replaced all our old wood/single pane windows with new vinyl low-e windows, and are planning on tackling the insulation after we rewire the place.
Currently, we take the heat up to 68-70 (depends on how cold we're feeling, but more likely up to 70) in the evenings after we get home from work. When we leave, we take it down to 63, as well as at night when we go to bed. We like the slightly cooler air temp at night, and just cover up with blankets, etc.
Should we be sticking to that 4 degree setback, or are we OK going to that 6-7 degree setback?