You do not mention which method you used but for something like emissivity normalization, it expects units of w/m^2*sr*micron.  If you are using ENVI 4.2 or later, ENVI automatically applies the published scale factors so that the bands are already in these units when the data is opened.  You can tell if the data is in floating point values.  In this case, the scale factors should be 1.0.