Many white and/or nearly white objects are in our living and working areas, such as documents written on white paper, white curtains, white clothes, and white walls and furniture. The perceived whiteness of these objects is important to the impression of lighting in these areas. To investigate the perceived whiteness in living areas, a series of experiments were conducted using four different fluorescent lamps in three different environmental conditions. It was found that the areas of perceived whiteness in the living areas were larger than the areas of perceived whiteness under achromatic conditions. Based on the results of these results, a perceived whiteness index is proposed for these experimental conditions.