By 2016 I had been selling whole house fans for 8 years. In that time I saw QuietCool introduce 2 rooftop whole house fans that pulled about 2000 CFM (cubic feet of air per minute). But they dropped that product. I saw that the Edmonds Hurricane rain hat could be a perfect hat for a new rooftop whole house fan. I called Allan Ramsay to ask if I could license his design. He said I could use it – they had no patent or other rights to it. But he asked that I not use their brand name, Hurricane. I used if for the first high performance rooftop, my Tornado Rooftop Whole House Fan. See it here – http://thorwaldsonwholehousefans.com/rooftopwholehousefan/