It doesnt work. And wont work. Thats why he hasnt come back when he got his first electric bill and it wasnt lower.
You cant get more energy out than youre putting in.
As it stands that is very true, however concerning everything, only the 24vdc 2000 watt Model PMG Generator $499.00 at 130% was a hoax in his statement. It doesn't add up. There is no point adding a 3kwh exhaust fan to blow air and get 3khw. Now if you have that 3kwh exhaust fan somewhere, adding the windmill fan turbine will give you some power back, in this case at least 1.5kwh but this is for another topic as this is getting something from wasted energy.
https://www.amazon.com/WINDMILL-Generator-controller-automatic-installation/dp/B01ASNP062?ref_=fsclp_pl_dp_4