I'm trying to wrap my brain around which is better use of gas dollars: to keep a constant day time indoor temp, when we are at work, or to program a 6 or 8 degree drop. We keep it at 72 when we are here, and drop back to mid-high 60's when gone. House is a 50's ranch with a high-eff. furnace, is well insulated, and has new widows. My HVAC guy says it takes more energy to bring it back up in the evening than it does keeping it constant. I'm just not sure. My insinct is that this is not a large drop in temp, so the work required to bring it back up is less than keeping it there all day, but I'm just not sure.