Developers of State Street Corp.’s new headquarters say design flaws that failed to take into account Boston’s frigid winters forced them to sacrifice leasable space and drove up project costs.

The 1.1 million-square-foot One Congress tower opened last fall on a portion of the Government Center garage property.

The developers, Boston-based HYM Investment Group and Carr Properties, claim that CBT Architects and engineering consultants WSP failed to notify them of the plans for a high-pressure heating system that malfunctioned.

The problems were identified by contractor J.C. Cannistraro during construction, according to the lawsuit submitted last week in Suffolk Superior Court. The Boston Business Journal first reported the complaint.

Developers hired an independent mechanical engineering consultant after Cannistraro said the high-pressure system would have “created an unsafe project due to unacceptably high pressures in the system piping,” attorneys for developers stated in the complaint.

WSP and CBT responded by proposing that mechanical and plumbing systems be added on the 28th and 29th floors previously allocated for tenant space.

Developers also determined that the building was only designed to provide freeze protection to approximately 7 degrees. Additional freeze protection pumps were required to be installed on the penthouse level. Additional costs associated with the freeze protection work totaled nearly $943,000, the lawsuit states.

And excessive noise from water condenser pumps discovered in June 2023 will require the replacement of pumps located on the penthouse level at additional costs, the complaint states.

The building was 100 percent leased prior to completion to State Street Corp. and Intersystems.

CBT declined to comment. WSP did not immediately respond to a request for comment.