I had a 50 year old Sears Homart gas furnace. It was about 60% efficient. I have upgraded to an 80% efficiency Lenox. The new furnace has a smaller fire box. The old one, I was told, was oversized. It has a flue gas damper. This seems to keep the bacement warmer. as the warm air comes out in the bacement not up the chiminey. It has a computerized circuit board. The board limits the fire box temp at first to allow for some heating up on cool days.On cold days it learns and switches to a mode that can heat the fire box all the way to 180F. The pump does not come on until the water box comes up to temp. I fail to see how tthis helps. It has a spark ignitor that eliminates pilot light waste. I can't wait to compare bills with my sister. Before we were running about the same on heating loads. I have done my part to help with global warming. Greata Thumberg.would like this. Frank Z
