Steel windows were a staple feature of the many early 20th century Tudor Revival homes built in Newton and Brookline. The narrow flat muntins in steel window sash approximated the leaded glass of the historic Tudor era and, paradoxically, gave the space a clean, almost modern feel. What is not to like about this unique and effective window solution?
Much has changed since the early 20th century, most notably the cost of heating fuel. The issue with steel window sash, unlike wood sash, is that it furnishes no thermal break. Steel, unlike wood, transmits the cold directly into the living space. Even if we were to equip the window with insulated glass, it will still transmit heat through the sash frame.
Certainly an interior storm window would mitigate heat loss, but these are casement windows and, unlike double hung windows, they are inoperable with storms in place. Clients are faced with a choice, to keep the steel casement windows and to deal with the issues - - or to replace them with new wood double hung windows. We vote to keep them, for the clean, elegant look, but then we aren’t paying the heating bills.