It was predictable. Elect a former public health commissioner to the United States Senate and wait for the recommendations about an unhealthy working environment. Royal Copeland entered the Senate in 1923 after a five-year term as commissioner of the New York City Board of Health. A practicing physician and a medical educator, the New York senator wasted little time in reaching a conclusion about the quality of the air in the Senate Chamber. He cited the deaths of 34 incumbent senators over the past 12 years and suggested that their lives had probably been shortened by the poor quality of the air in the chamber. In the winter, the dry heated air was blamed for the spread of influenza, bronchitis, and the common cold; in the summer, excessive heat and humidity sapped members' energy and tested their tempers.
In June 1924, as the increasingly warm late spring days again called attention to this perennial problem, the Senate adopted Senator Copeland's resolution directing Capitol officials to consult with leading architects to develop a plan that would improve the "living conditions of the Senate Chamber."
The firm of Carrere & Hastings, which had designed the Russell Senate Office Building a generation earlier, quickly produced the requested plan. The architects proposed converting the chamber's configuration to that of a semi-circular amphitheater, lowering the ceiling for improved hearing, and removing several walls to extend the room to the Capitol's northern wall. In removing these interior walls, the Senate would have to sacrifice the Marble Room, the President's Room, and the vice president's formal office. To brighten the chamber's dreary interior, Carrere & Hastings proposed the addition of three two-story-high windows in the outer wall, along with a ventilating apparatus to draw fresh air into the chamber.
On May 11, 1928, the Senate approved funding of $500,000 to accomplish the project. Five days later, however, Senator Copeland abruptly requested that his proposal be "indefinitely postponed" because it was "no longer necessary." The reason for this sudden reversal lay in a separate appropriation of $323,000 to produce a ventilation system that had been endorsed by a team of public health experts. Tests demonstrated that the chamber could be made comfortable and healthy—without the cost and disruption of knocking down walls—through an innovation, designed by the Carrier Corporation, known as "manufactured weather." Work began early the following year and, by August 1929, the Senate had in place its first air conditioning system.
U.S. Congress. Senate. History of the United States Capitol: A Chronicle of Design, Construction, and Politics, by William C. Allen. 106th Congress, 2d sess., 2001. S. Doc. 106-29.