1 maybe 5$ a year. 2 maybe 8 $ a year.
3 zero, and your fan may not last and electric should go up. 4 ?
maybe zero.
Payback? how long will you live there. If you are very lucky you are at
80%. and a 94.5% unit will save 18%. So say you are at 75% a 94.5% unit
will save apx 26% and that is at todays gas prices, in ten years gas
will probably be double