PNNL

In addition to cost-effective, year-around energy savings, modern storm windows can offer a modern design and aesthetic to a home. Image Courtesy of Larson Manufacturing

The U.S. Environmental Protection Agency (EPA) formally released a framework document to develop an ENERGY STAR label for low-emissivity, or "low-e", storm windows. The framework document uses market assessment research, building modeling, and Lab Homes research performed by PNNL and sponsored by the Department of Energy's Building America program and the Northwest Energy Efficiency Alliance.

This document is the first step in getting the EPA's stamp of building efficiency approval—that iconic blue label with scrawling script and a star

As highlighted in October, PNNL tested the technology at the Lab Homes where the energy consumption of a home with low-e storm windows was compared to an identical manufactured home in the same area without low-e storm windows. The Lab Home results demonstrated about a 10 percent annual energy savings when low-e storm window attachments were installed over double-pane glass windows. Another PNNL report cited by the framework document shows an energy savings of 10-35 percent depending on climate zone, baseline window conditions, and the type of heating system. In addition, various PNNL market assessments show a payback on investment of five years or less when installing low-e storm windows.

PNNL scientist Katherine Cort said, "We want to get the word out that these are not your grandma's storm windows. It's always cost-effective to choose a higher efficiency low-e storm window over a clear glass panel."

Adopting low-e storm windows into the energy-efficient arsenal of ENERGY STAR-labeled products is anticipated to increase market adoption rates. The EPA cites a “lack of recognition by energy rating and certification systems” as a reason for low market adoption.

The ENERGY STAR label gives consumers an energy-efficiency cheat sheet they can rely on when comparing multiple storm window products. Because storm panels are installed on approximately 500,000 homes nationwide annually, the ENERGY STAR label could have far reaching impacts on reducing residential energy use.

Product performance results and market assessments performed by PNNL are cited in the framework document. The final ENERGY STAR label specification is scheduled to be effective in 2017.

For more information on how to properly install low-e storm windows visit the Building America Solution Center. For more information about how a product earns the ENERGY STAR label click here.

PNNL Research Team: Katherine Cort, Theresa Gilbride, Marye Hefty, Jake Knox, Cheryn Metzger, and Joe Petersen