New Double Glass in Old Windows?

Does anyone know if it’s possible to replace an old single-paned glass window in a brownstone with new double-paned glass that would provide better insulation? These are floor-to-ceiling parlor floor windows, with four panes per window, but very thin glass. Is it possible to make them more energy-efficient, and if so, any recommendations for who can do this?
Thanks.

By de95 |