m Ransley wrote:
The difference of % efficiency gained inbetween two units is calclated
by the difference in percentage of the 2 units. Or 80% is 18% different
than 94.5%. I had a hard time accepting this till I asked Lennox.

Well, Lennox doesn't know what they are talking about. Let's say you
spent $100 on natural gas. At 80% efficiency, that produced $80 worth
of heat, the other $20 was wasted. To produce the exact same $80
worth of heat with a 94.5% furnace requires 80/.945, or $84.6 worth of
natural gas. $84.6 X .945= $80. So, instead of spending $100 for
gas, you spend $84.6, which is 15.4% less. It's pretty simple and
straighforward.




So
people upgrading to more efficient units really achieve higher percent
savings then they usualy realise. Repairs are always an issue, 10 year
warrantys are what should always be obtained especialy with VSDC
blowers. My numbers show a 6 year payback on a 500$ replacement blower
for me, but that is todays Kwh cost, soon I am going up 15-20%. With a
10 yr warranty I am ahead no matter what happens. Another point is how
many factor in past Ng price increases to reflect future costs into
their payback, there again payback is quicker with a higher efficiency
unit.