The Attachments Energy Rating Council (AERC), an independent, public interest, non-profit organization whose mission is to rate, label and certify the energy performance of window attachment products, has launched a new arm to its certified products category. Commercial Secondary Windows are retrofit products that attach to the interior or exterior of existing windows and provide an enhanced insulating barrier between the window and the outdoor environment, minimizing the infrared energy that can pass through and reducing air infiltration. Secondary windows offer a significant, cost effective opportunity to address energy performance and comfort in commercial buildings and reduce energy costs. In fact, for mid- to large-size commercial buildings with low performing (single pane or clear double pane) windows, secondary windows can achieve similar performance to full window replacement for 30-50% less cost.

“AERC is pleased to welcome a new component of our rating and certification capabilities with the launch of the Commercial Secondary Window program,” says Ralph Vasami, executive director of AERC. “We are excited to have entered into a new sector of the market and to work with our commercial and utility partners to promote the energy-saving benefits and certified ratings of these products.”

AERC recognized the potential of secondary windows and prioritized the development of a commercial rating and certification program in order to provide the industry with credible data on the energy performance of these products. The commercial secondary windows program adopted similar, rigorous performance metrics used by AERC’s residential program including U-factor, Solar Heat Gain Coefficient (SHGC), Visual Transmittance (VT) and Air Leakage. AERC-developed ratings and certification procedures aim to help accelerate awareness and adoption of these products as an energy savings measure by enabling:

  • Efficiency organizations and gas and electric utilities to develop energy efficiency programs to offer customer incentives and rebates for purchasing AERC certified secondary window products;
  • Simulations of whole building energy performance for projects using AERC ratings as inputs; and
  • Commercial building owners, ESCOs, facility managers and architects to use AERC ratings to compare the performance of secondary window products and make purchasing decisions based on energy performance metrics.

The Northwest Energy Efficiency Alliance (NEEA) provided support to AERC for program development, manufacturer certification and market adoption. Third-party certified commercial secondary window ratings generated through AERC will help inform NEEA’s Window Attachments Program and overall market transformation goals. NEEA, an alliance of 140 utilities and energy efficiency organizations in the Northwest (Oregon, Washington, Idaho and Montana) is running a field study in 2020 and 2021 to validate energy savings in the region.

Additional program support comes from Consolidated Edison (NY), which is also running a pilot in the New York City area in 2020. Both pilots use AERC’s new commercial secondary windows program and leverage the ratings information to inform their product choices and evaluations.

“AERC’s Commercial Secondary Window Program is a key element in NEEA’s field study,” says Elaine Miller, market transformation manager, lighting and building envelope at NEEA. “The third-party ratings generated through the commercial certification will provide Northwest building owners and decision makers with a third-party, real-world basis for comparison in selecting products that support higher building energy performance.”

In addition to the field study, Miller also explains that AERC rated and certified secondary window products offer building owners a key, cost effective tool to improve their building’s envelope performance.