Pico Rico wrote:
A friend has a house in the mountains. No A.C. The furnace is as old as
the house, probably 1965 or 1970. Are new furnaces more efficient in their
use of natural gas, and thus "pay for themselves"? If so, how does one
calculate the anticipated savings and pay back period?


Hi,
New high efficiency furnaces are as high as 98%. Regardless cost, up
here in Canada lagally low to mid efficiency furnace can't be installed
on new install. Think your friend's furnace is not even mid
efficiency(80%) being that old.