(Photo: 195 Church Street interior. Credit: Apogee Enterprises)
Extensive retrofits to an 18-story concrete office building in New Haven, Connecticut, are expected to shave $203,000 annually from the owner’s electricity bill.
Located on the New Haven Green at 195 Church Street, the 244,000-square-foot Class A office building originally constructed in 1975 had aging windows, all-electric baseboard heating, and a variable-air-volume system with electric reheat that led to soaring annual electricity bills, according to the retrofit strategy team from Apogee Enterprises.
The building’s property management company Northside Development Co. collaborated with Globelé Energy to improve the building’s energy efficiency. They reviewed the property using the DOE’s benchmarking program and performed a Level 1 ASHRAE energy audit. Work on the $6 million energy-efficient window and lighting retrofit started about two years ago.
Globelé’s multi-phase plan for 195 Church Street called for replacing the old fluorescent lights with new LEDs and updating the windows. In order to select an optimal window system, Apogee’s team used a physics-based energy modeling software tool that simulates annual building performance. They were able to forecast how much energy could be saved by adding an interior accessory window with low-e glass to the existing glazing.
As a result, interior accessory windows from Wausau Window and Wall Systems that contain low-e glass and have aluminum framing were selected. Renovations started in summer 2016 and much of the window retrofit was completed by May 2017. The full retrofit calls for updating 1,400 window units totaling 42,336 square feet.
Since December 2015, the architectural firm for the building, Kenneth Boroson Architects, has installed 9,000 LED lamps and 1,400 energy-efficient window inserts. A Globelé analysis of the new window units paired with the new LEDs projected 29% savings in annual electrical energy consumption.
“The year before we bought this building, the electric costs were approximately $1.2 million per year,” said Christopher Vigilante, COO for Northside Development. “We believe that through correct energy purchasing and our load reductions from our energy savings programs, we will reduce our bill by 50%.”
The building is also on track to earn an estimated $589,000 rebate from regional electric distribution company United Illuminating through the Energize Connecticut initiative, which aims to advance the efficient use of energy, reduce negative environmental impacts, and promote economic development.
“Electrically heated buildings are a great candidate for energy efficiency measures and these types of projects are exactly what we look for at UI,” said United Illuminating energy engineer Gary Pattavina. “We recognize new energy-efficient windows are a costly investment and the incentives available to our customers help bring that up front cost down significantly.”
Windows play an important role in large office building retrofits. A comprehensive retrofit for New York City’s iconic Empire State Building that started in 2009 is expected to save $4.4 million this year, according to the building’s ownership. Among the changes was a window project that involved upgrading the existing insulated glass for around 6,500 double-hung windows to include suspended coated film and gas fill.
“This project improved the thermal resistance of the glass from R-2 to R-6 and cut the heat gain by more than half, in addition to allowing for the recycling of all existing glass — 96% of the original glass and window frames were reused,” according to the building management.
The 3rd Annual Environmental Leader & Energy Manager Conference takes place May 15 – 17, 2018 in Denver. Learn more here.