Insulated glazing units comprising first and second sheets of glazing material with a low pressure space there between are described. The major surface of the second sheet of glazing material not facing the low pressure space has a low emissivity coating comprising at least one layer of fluorine doped tin oxide thereon. There is a first anti-iridescence coating between the low emissivity coating and the second sheet of glazing material. Also described are insulated glazing units comprising three (first, second and third) sheets of glazing material with a low pressure space between first and second sheets of glazing material, and a second space between the first and third sheets of glazing material. There is a low emissivity coating on one or both major surfaces facing the low pressure space. The third sheet of glazing material has a low emissivity coating on both opposed major surfaces thereof.