Vertical axis windmills have been around ever since the 9th century when early Persians used them to harness the power of the wind to pump water and grind their grains. This design has stood the test of time and is still being used today in the form of the Savonius wind turbine.
Around the turn of the century a Finnish engineer by the name of Sigurd J. Savonius introduced the vertical axis wind turbines or VAWT, a revolutionary design of wind turbine that is not only reliable but is also very easy to build. It was previously used for installations that requires generator that produces small amounts of electricity that is very dependable. This design of wind turbine is the most used for modern anemometers as well as sea buoys that only require a bit of power for maintenance.
The Savonius wind turbine is also the design of choice when choosing wind turbines to supply renewable energy for common households. This is because as compared to the horizontal axis wind turbines the Savonius design is quieter, which means you won't get any calls from the homeowners association telling you to take down your noisemaker of a generator. And also because of the compact blade design it poses less of a threat to birds and other flying creatures.
And since the blades are mounted on a vertical position it can catch the wind that comes from any direction, so there's no need to rotate the thing whenever the wind changes direction. Horizontal wind generators are mounted on a pivot which allows it to swivel to the direction on which the wind is coming from, and while the blades are tracking the wind no electricity is being produced. The Savonius design is much more efficient because of its vertical orientation it can always collect the passing breeze which the horizontal design might miss, no matter how weak the wind might be.
Another nice advantage of the Savonius windmill is that the shaft of the generator can be placed nearer to the ground, meaning there is less weight at the top of the tower. Because of the lower centre of gravity there is little need for the tower to be stabilized.
Because of its simple design you can save a lot of time and money as compared to the standard horizontal installation because it needs less hardware to secure it properly, thus resulting in a lower cost, which means you can regain your initial investment faster and will cut your electricity bill to just a fraction of what it was before.
And as with most machines, if there are fewer moving parts there is a lesser chance of the windmill breaking down. And if it does need a bit of preventive maintenance it can be done easier because of the vertical shaft that allows the generator to be placed at ground level.
Having a windmill to utilize the wind's power to generate electricity for your home is a very earth-friendly thing to do, but if you really want to get the most out of this renewable source of energy then you should choose the Savonius wind turbine.