I've got three sets of exterior doors on the back of my house that are still single pane glass. Two single doors with sidelights and one set of french doors. The doors themselves are in good shape and are made of wood.
We have been thinking of upgrading them to get some doors with insulated double pane glass but it won't be cheap. Is it feasible to just remove all the glass in the existing doors and replace it with a single pane of insulated glass?
You can see all the doors in this picture. I'd replace them with a single pane to match the windows that were thankfully upgraded before we bought the place.
House by
willtel, on Flickr