Address selection

Postal codes were retrieved for every home situated within a 2.5 km radius of the wind turbines included in the research. At distances over 2.5 km the sound of a wind turbine is hardly noticeable, because it will usually be below the ambient sound level due to other natural (wind) and manmade sources.

Because we were interested in perception of wind turbines by residents only, we excluded companies and institutions from our database. At close distance to the wind turbine, all the postal codes were used. Farther away, where a high number of people live, a random selection was used.

A total of 1948 addresses complied with our research criteria. For these addresses, the sound power levels and the 'fraction of view' were calculated for all (including smaller) wind turbines as they would be perceived at the residence. Also, a questionnaire was sent to these homes.