On Treehugger this week, Lloyd Alter noted a new glass product which includes a heating element between the panes, allowing the window to "function as a radiant heating system." Alter asks: Could this be the least sustainable building product ever invented? In the comment section, Alter says: "I still suspect that a whole lot of the output of this thing is heating the great outdoors."
He's absolutely correct, and this is worth a bit of discussion because it's (yet) another example of an issue where green builders would be well-served by knowing their history better.
Le Corbusier figured out that heated glass was a bad idea in the 1930s, or at least he should have. Prior to that, he had been wondering if it would be better to heat and cool the walls of a structure rather than heating and cooling the air inside the rooms. He developed a concept he called the mur neutralisant (neutralizing wall), essentially a double-skin glass wall with an air cavity that was heated or cooled mechanically. He began working with engineers at the American Blower Corporation to demonstrate the practicality of the concept. Those engineers surprised Le Corbusier with their analysis:
"Your proposal will demand approximately four times more steam and more than twice the fan energy to heat and ventilate the building than that which would be necessary with the current methods employed in our country to heat and ventilate a building exposed to the same atmospheric conditions."
Nevertheless, Le Corbusier used the mur neutralisant in the Cite de Refuge building (Paris, 1930-33), and it was an unmitigated disaster, especially because the cooling could not keep up with summer overheating. The system needed to be replaced within a few years. (To his credit, Le Corbusier next turned his attention to the brise-soleil.)
This is a simplified version of a complex story. More nuance and detail can be found in the following sources:
Harvey Bryan, "Le Corbusier and the "Mur Neutralisant": An Early Experiment in Double Envelope Construction," Proceedings of the Ninth International PLEA Conference, 1991.
Harris Sobin, "From L'Air Exact to L'Aérateur: Ventilation and its Evolution in the Architectural Work of Le Corbusier," ACSA Annual Meeting, 1996.