The winter winds they are a-comin, and while very few people are about to build a 30 to 50 foot tower in their back yard, there are some solutions for those looking for a slightly less involved project.
Rooftop wind turbines are often panned by the perfectionists among microwind early adopters. This is because the turbine doesn't get every last drop of wind it could -- a cushion of air forms around a building and prevents high speed winds from reaching the turbine. Several wind power guides advise on proper turbine placement for optimal wind capture.
But perfectionism so often is the enemy of progress. Another approach is to make the turbines and their mounting cheap enough that they make financial sense despite their suboptimal placement. Read on...
Rooftop turbines use the existing structure of a house to get the turbine aloft where it can catch decent winds -- not the best winds, as stated above, but "good enough" if your turbine is cheap. There are limits -- your house wasn't intended to be used as a wind tower when it was built, so the turbine cannot be too large. But every bit counts. If you get a lot of wind, a rooftop turbine might be more affordable than you think.
The first choice to make is... VAWT or HAWT? If you have prevailing winds, HAWTs are more common and as such, often cheaper. The popular "Air X" model from Southwest Windpower prices in at a modest $500+, or about a buck and a quarter per peak Watt. A good number of available HAWTs, along with prices, can be found here. For those willing to take a chance on a startup, another interesting and cheap design is here.
As a side note, the Air X seems, at a glance, to be the turbine selected for the energy-autonomous golf-cart-like urban vehicle recently making press
If your wind is more unpredictable, or you've got a lot of yardbirds, you might look into a VAWT. Unfortunately as a relatively young market, pricing figures for VAWTs vary wildly and there isn't much in the way of a "Consumer Reports" to put manufacturer's claims to the test. A good number of VAWT manufacturers are listed here, and I diaried a bit about them before.
Britain, of course, not having as many pessimistic cynics as we do per capita, is way ahead of us in both HAWT and VAWT commercialization and rooftop deployment, with the "Swift Wind" and "Windside" products gaining in popularity there along with more conventional "Windsave" models.
Another prospect that might be of interest to those thinking of building their own home is to design for wind power. Houses with rounded roofs would allow wind to flow over undisrupted, and perhaps even enhance the performance of a roof turbine beyond that of a tower turbine. Of course, one must take into account that a round roof is essentially a big airplane wing and design for the fact that the roof will actually try to lift off the structure :-). Despite this hitch, dome shaped homes are being investigated for their hurricane resistance.
If hurricanes aren't a concern for you, a cheaper option might be the strategic placement of greenhouses or solar panels in the yard around a structure to amplify prevailing winds across the roof.
Finally, in a fit of retro-engineering, a team of engineering students from Oregon State University has developed a wind-powered water and space heating system, which might make an excellent DIY project, given that one need not deal with the nuances of electricty and power point tracking and batteries. Though heat is not nearly the premium form of energy electricity is, such projects might make sense due to their sheer simplicity -- and winter winds are precisely what causes those chilling drafts, so the heat would be available at exactly the right time.