60% efficient gas furnaces are now outlawed for sale in the USA. At
60% efficiency, I pay a total of no more than $250 (at today's gas
prices) to heat my house for the entire heating season. To go up to
80%on a new furnace has a payback period LONGER than the furnace's
expected lifetime. The only way to economically justify going to an 80%
furnace is to assume that gas prices will at least double over the
lifetime of the unit, and even then the payback is marginal.


this is bs.

Even a 90 percent gas furnace only costs less than 2k, and by my
figures, you would save 84 a year by changing to that. If a 2k furnace
doesn't last you 20 years, you bought poorly, and that is 1680, and
there aint no furnaces for sale at 320 bucks

Hell, I'm fullo it, there are 93 percent efficient furnaces for sale on
ebay right now for less than a grand,800 bucks even. looks like no more
than a few hundred difference on the cost of the unit. Absolute no brainer.