I've recently beccame more interested in wind power and have done a lot of research. I've found all the hype about modified automotive alternators modified for wind generations and the fallacies of them. I found this company to produce the most reasonable PMA with accurate wattage to wind ratings. I have also found very useful info in these forums, including the link to windspeed page. This leads me to the math. There are 8766 hours in a year (24*365.25). I consumed 7250 kwh in 2011. My average annual windspeed is slightly above 11mph. The Windtura 750 chart shows a production of about 75w @ 24v @ 11mph. The average annual production I can expect from the 750 is 657.45kwh. This equates to 9% of my consumption, representing a cost savings of $52.60 annually (@ .08/kwh - my cost). If we assume that to put a GTI system only (no batteries) using the 750 would cost about 2x the cost of the 750 alone by the time the GTI and all other items required are included, then we are talking approximately $2,000. That would make the system pay itself off in just over 38 years. If I trebled my investment, I would reduce the time by third to 12.7 years. Unless somebody can find an error in my math, it isn't really worth the invest for me, is it?