"Ian" wrote in message
"Estimated savings for a typical home from replacing single pane with
ENERGY STAR qualified windows are significant in all regions of the
country, ranging from $125 to $340 a year."

So I'm paying about $2500/year for gas heat in the winter and Electric
A/C in the summer. So if I replace 27 windows in my house at an
approximate cost of $800 each or total of about $20, 000 it'll take 66
years before I break even,

They are using averages. I'd say the average house has much less than 27
windows. You may, in reality, get payback in only 45 years.