What CFL's Did For Lighting, Enerlogic Films Do For Windows

What Enerlogic has come up with in their window film is really great.  It keeps the heat outside in the summer and inside in the winter. It will essentially make a single pane window perform like a double- pane and a double-pane perform like a triple pane.  It is a very cost effective product that may pay for itself in energy savings in as little as a couple of years.  It may also be eligable for a Federal Tax Credit as well, offsetting the initial cost.  Check out the links, it's cool stuff.