Gregory Rochlin was completing a window preservation project at Boston’s historic Faneuil Hall in 2015 when city officials asked him to assess the condition of the mechanical attic in the public building. Rochlin climbed a narrow ship ladder to access the space. When he arrived, he was shocked to find air handlers the size of Volkswagens stuffed into an attic reminiscent of a submarine.

When asked what it would take to replace the 25-year-old mechanical system before its service life expired in 2020, he was dumbfounded. “My first reaction was ‘You cannot be serious,’” says Rochlin, a senior project manager for CSS Architects Inc.