A vertical-axis wind turbine apparatus comprising: a substantially vertically-oriented main shaft; a blade assembly coaxially aligned with and rotatably engaged about the main shaft, the blade assembly providing an at least one blade radially projecting therefrom; the blade assembly having a circumference that comprises a catch portion, wherein the at least one blade catches the wind, and a return portion, wherein the at least one blade carries out its revolution about the main shaft before returning to catch the wind once again; and a housing rotatably engaged with the main shaft and configured for selectively encompassing the blade assembly, the housing comprising: a housing frame, wherein a bottom end of the housing frame is rotatably engaged with a base plate integral with a lower end of the main shaft; a first screen integral with the housing and configured for shielding the return portion of the blade assembly circumference from the wind; a second screen rotatably engaged with the housing and configured for selectively moving between a retracted position, wherein the second screen is positioned substantially adjacent to the first screen such that the catch portion of the blade assembly circumference is exposed, and a deployed position, wherein the second screen is rotated away from the first screen for at least partially shielding the catch portion from the wind; a housing top positioned proximal an upper end of the main shaft; and a weather vane fixedly mounted on the housing top and configured for causing the housing to selectively rotate about the main shaft and orient the catch portion of the blade assembly circumference into the wind; whereby, during use of the apparatus, the second screen is capable of selectively moving into the deployed position upon the occurrence of pre-determined environmental conditions that would otherwise potentially damage the blade assembly. a substantially vertically-oriented main shaft; a blade assembly coaxially aligned with and rotatably engaged about the main shaft, the blade assembly providing an at least one blade radially projecting therefrom; the blade assembly having a circumference that comprises a catch portion, wherein the at least one blade catches the wind, and a return portion, wherein the at least one blade carries out its revolution about the main shaft before returning to catch the wind once again; and a housing rotatably engaged with the main shaft and configured for selectively encompassing the blade assembly, the housing comprising: a housing frame, wherein a bottom end of the housing frame is rotatably engaged with a base plate integral with a lower end of the main shaft; a first screen integral with the housing and configured for shielding the return portion of the blade assembly circumference from the wind; a second screen rotatably engaged with the housing and configured for selectively moving between a retracted position, wherein the second screen is positioned substantially adjacent to the first screen such that the catch portion of the blade assembly circumference is exposed, and a deployed position, wherein the second screen is rotated away from the first screen for at least partially shielding the catch portion from the wind; a housing top positioned proximal an upper end of the main shaft; and a weather vane fixedly mounted on the housing top and configured for causing the housing to selectively rotate about the main shaft and orient the catch portion of the blade assembly circumference into the wind; a housing frame, wherein a bottom end of the housing frame is rotatably engaged with a base plate integral with a lower end of the main shaft; a first screen integral with the housing and configured for shielding the return portion of the blade assembly circumference from the wind; a second screen rotatably engaged with the housing and configured for selectively moving between a retracted position, wherein the second screen is positioned substantially adjacent to the first screen such that the catch portion of the blade assembly circumference is exposed, and a deployed position, wherein the second screen is rotated away from the first screen for at least partially shielding the catch portion from the wind; a housing top positioned proximal an upper end of the main shaft; and a weather vane fixedly mounted on the housing top and configured for causing the housing to selectively rotate about the main shaft and orient the catch portion of the blade assembly circumference into the wind; whereby, during use of the apparatus, the second screen is capable of selectively moving into the deployed position upon the occurrence of pre-determined environmental conditions that would otherwise potentially damage the blade assembly.