<html> <head> <style> .hmmessage P { margin:0px; padding:0px } body.hmmessage { FONT-SIZE: 10pt; FONT-FAMILY:Tahoma } </style> </head> <body class='hmmessage'> Hello, I want to model a low-e coating on a new window construction.  As far as I can tell, materials (i.e. glass) are defined as homogeneous in the materials library, and thus have a single emissivity value.  However, clearly a low-e coating will cause the glass to have two different emissivity values.  Could anyone share how they have modeled this? Also, it would be useful in future versions of ESP-r to have fill gases other than air.  I know the properties of the air can be changed, but it would save a step to be able to choose argon or krypton, for example. Thanks! Liam O'Brien <hr />At a loss for words? Find them by playing Seekadoo! <a href='http://g.msn.ca/ca55/208' target='_new'>Play now!</a></body> </html>