Just how much noise do turbines really make?

Taking a look over at the graph on the right, a wind of 13m/s is considered a strong breeze (umbrellas are hard to use at this speed). This model turbine only gives off about 30 Decibels of noise, which if you look at the chart below, you’ll see falls into less noise than a library background noise – so it’s a reasonably quiet device.
Most of the noise you hearing here is also background noise from the wind.  Comparing this to the noise levels we experience every day measured in decibels (DB), distinguishing the noise from the turbine is difficult at best.

31-45 dB is considered a faint  noise zone
This is the decibel level of quiet sounds. In this range, sounds are audible but you may have trouble distinguishing them from other sounds if you are somewhere noisy.  Soft conversation (like what you might hear in a library) falls into the 35-decibel range.

Turbine Blades have become a science
Over the past few years, turbine blades have become a science, with supply companies owning various design patents. The LX range in particular has patented blades designed for maximum efficiency in mind.  Efficiency equals low noise and maximum power delivery to the generator unit.

Larger and less noise
The smaller the turbines the higher rotation speeds of around 500RPM in a good wind, giving you the renowned whistling sound in higher winds.  But this is not the case with the larger turbines, we have found the sound drops off dramatically, with even further drops on the high voltage variable blade pitch turbines.

The larger turbines have larger blades to get the torque needed to turn the generator.  This means the blades are longer and turn slower.  The rotation speeds top out at between 150 and 200 RPM.

At our test site in the Western Cape, the LX 3000 we had running for a few years was reasonably quiet due to it’s superior blade design.  In April of 2024, we put up a High Voltage variable pitch turbine (HV-VP-T-3KW-350V)  This unit is even quieter than its LX3000 counterpart, the blades aren’t even comparable to the LX unit in design but it whispers along and does its job like a star.