Optimum Steel Windows Chicago |top| Jun 2026

Chicago energy code (IECC) has strict U-factor requirements. For most residential projects, choose Optimum’s thermally broken options with double-pane, low-E glass to pass inspection and reduce heating bills.

Whether you are restoring a landmark property or designing a contemporary residence, here is why Optimum Window Mfg. Corp. is a top contender for steel windows in Chicago. Why Choose Optimum Steel Windows for Chicago Projects? optimum steel windows chicago

: Optimum is the largest U.S. manufacturer of fire-rated steel windows, essential for specific Chicago building codes in dense urban areas. Chicago energy code (IECC) has strict U-factor requirements