Well, been doing some real testing finally, temps low 20's at night, highs low 30's in day. Was running smartstat, program 3, heat 3. Tue. night , rev shut down around 11 p.m., started around 1 a.m., shut down around 3 a.m., chilly when I got up at 4, stat set at 62, temp 63, inside, outside 24. Was just starting back up at 5 when I left for work. Last night (Wed), switched to t'stat, set at 64, prog. 3, heat 2. Got up this morning, inside 65, outside 20. Got home this afternoon, outside 33, inside 72 (too damn hot for me but wife was lovin' it ). Gonna leave it there tonight, switch back to smartstat when I go to work, in the morning, will probably shut down, clean it when I get home, go back to t'stat during overnight hours , smartstat days (until it gets REAL cold out). Get a fair amount of passive solar here when sun shines, so would be good to have it down on sunny days. Wife is ecstatic. Oh, yeah, about 1 1/2 bags Pennington in 24 hours.