While attending the 2016 National Trust for Historic Preservation conference in Washington DC at the Hilton where the Beatles last stayed. This is where I met 2 young ladies from the DC historical society.
They told me the story of a beautiful 1928 Building on Dupont Circle, shaped like an arrowhead at 1350 CT Ave NW Wash DC, with the back of the building facing 19th St.The 12-story building was originally built as a hotel, is now office space. The street level is stores and restaurants. The 2nd through 12th floors has nearly 1000 beautiful original double hung wood single pane windows.
We met with the building owners who desperately needed to get the Heating and Air Conditioning costs under control, while also dealing with the DC Historic Society, who insisted that they could not just toss out the historic windows and put in replacement windows. They had been at odds for months, until the DC Historical Society brought us in. Our solution was to give each side what they wanted and needed. We proposed to leave the historic wood windows in place (To make DC Historical happy), and install 968 Interior Low E Glass Compression Storm windows. (To make the Owners happy with Year-round Energy savings and comfort.) With our windows on average saving 20% on annual energy costs it is less than a 5-year payback. By the 6th year and onward the savings are pure profit.
As an added benefit, the storms also are good at soundproofing. This was pointed out to us by one of the tenants, whose windows at the 2nd floor was right above some Street Musicians who would gather all day on the sidewalk and play for tips.She was at wits end, because she was more musically talented than they were, and was wanting them to get mandatory music lessons. This flashpoint was avoided because she could no longer hear the street musicians.