Idea for vertical axis attic heat powered
 

I was thinking about this one again yesterday. I was working in the hills and saw 2 large horizontal turbines, maybe 3 meters each just above the tree tops, not spinning! What a waste. They should have been much taller. I noticed the neighbor's whirlybird attic vents were moving right along. I know it takes a lot more power to turn big propellers especially against an electrical load, but perhaps you could generate some micro wind from your attic heat and or the wind. Just throwing it out there, not sure the best way to implement it but there's no shortage of attic heat where i live.

I'm not sure it would ever pay for itself. Plus the reduced air flow due to more fiction on the wind turbines might keep more heat in the attic longer, off setting the power savings. I have seen some pretty cool vertical wind turbines, but the general rule of thumb (heard from several turbine guys) 12mph of wind= 100 watts of power. The math just doesn't add up in my eyes. I looked into buying the cheap ebay micro turbines but they just won't make enough power to be worth the trouble.
Either buy a good sized turbine and mount it as high as you can, or spend the money on solar.
Just my 2 cents

Yep, cheap solar has pretty much killed small wind!

As a once upon a time small wind turbine builder I agree, there are few places where a wind turbine is more viable than PV.
My units were designed for use on sailboats, and were I still cruising would expect my wind turbine to out perform a solar array $ for $.
For almost every other application PV wins, no moving parts, no management hassles in high winds no noise etc.