We're showing you lots of green gadgets this week, and a great example is the Windterra Eco1200, a wind turbine that can reduce your energy bill by $75 per month. Sitting up on your roof top, it doesn't matter which direction the wind is blowing, because a mere 6.7-mph breeze can set this omnidirectional windmill in motion, generating 1600 kWh per year if your winds average 11.18 mph.

It's quiet, too, because it has a automatic brake that keeps it from spinning faster than 225 rpm, where it will be noisy enough to bother you and your neighbors. Compared to solar energy, this wind turbine is relatively inexpensive, costing around $7,000 installed including the turbine, mounting materials and an inverter that turns that wind energy into electric power. A couple of Eco1200 turbines like this or this Skystream 3.7 wind generator, teamed up with the solar array on your roof might let you go off-grid, not paying power companies but selling your excess energy back to them. — Charlie White

Windterra, via Treehugger