I know my thermal pane wood door has lost it's seal and is clouded. Can i order the replacement glass and instal it myself?

Many times depending on the application of the glass if it is double pane style there may be a gas involved between the panes. It helps keep down condensation. The gas is inert but you have to install it a certain way so it gets in there (purge). It may be best left to a professional if that is what's needed in your application. Also if your glass is still in good shape that may be all that's needed is to reinstall as gas between the layers.