Change On the Horizon for Energy Star Criteria?

Changes proposed by the Washington, D.C.-based U.S. Environmental Protection Agency to Energy Star window, door and skylight standards have generated discussion and controversy in the industry. Some major manufacturers and industry associations, for example, have expressed concerns about product-development costs associated with increasingly ambitious energy efficiency goals. Revised criteria are expected to take effect in 2013 and there are multiple opportunities for public input over the coming months. Efficient windows being among the most popular remodeling measures, this process will greatly benefit from remodelers' perspectives.


In October 2011, EPA released a framework document with initial revision ideas and accepted a first round of comments. Some of these ideas received strong stakeholder support. For instance, there is broad agreement that installation instructions should be made available by Energy Star partners. More contentious issues are the revision timeline and EPA's proposed U-factor and solar heat gain coefficient (SHGC) criteria ranges. Currently about 80 percent of windows sold nationwide qualify for Energy Star, making it almost a competitive necessity to sell Energy Star-rated windows.

The tentative timeline for the Energy Star Windows, Doors, and Skylights criteria revision aims for new specifications to be published in September 2012 and to take effect in the fall of 2013. This will be preceded by two criteria and analysis reports, a stakeholder meeting, and two public comment periods between March and August 2012.

The criteria selection is more straightforward for the warm or moderate climates—the Southern, South Central and North Central climate zones—where triple glazing will not be needed. The vast majority of Energy Star windows currently have dual-pane low-E glass, argon gas fill, warm edge spacers and low-conductance frames. With few or no modifications, these windows would meet the proposed criteria for all but the Northern climate zone.

Northern Zone May Be a Game Changer

In the Northern zone, the criteria revision could have a more dramatic effect because the proposed reduction of the U-factor to between 0.25 and 0.27 is challenging with dual panes. EPA's intent for the Northern zone criteria is to recognize the highest-performing dual-pane windows and encourage a greater number of triple-pane windows. If equipped with high-performance frames, windows with triple panes or with a suspended film between two panes often achieve U-factors around 0.2, but Energy Star does not yet give special recognition for such performance. These window options are available from many manufacturers, though at a price premium, which has so far kept them from becoming a mainstream choice. While EPA's initial criteria proposal for the Northern zone could also be met by the highest-performing double-pane windows, this too would likely require modifications to the frame and glazing that would increase production cost.

Industry reactions indicate the Northern criteria are the most contentious aspect of the revision process. Major industry associations and manufacturers are voicing concerns about the effect a move to the triple-pane performance range would have in the current economic situation. Manufacturers' abilities to invest in major product upgrades is limited and higher prices might suppress consumer demand. Some manufacturers, however, see an opportunity to more strongly distinguish their high-performance products. Possibly, a push toward triple-pane windows could also result in lower incremental cost through economies of scale, though this may require a somewhat more vibrant market.

Inclusive or Exclusive?

Overall, the question for the Northern zone is whether Energy Star criteria should be more inclusive or more exclusive. More inclusive, easier to achieve criteria close to current levels would mean Energy Star windows retain the majority of the market, ensuring most consumers opt for energy-efficient windows at a reasonable price. To allow greater differentiation in the market, on the other hand, the criteria would have to become more exclusive, focusing the program on very efficient products that cost significantly more—unless innovation reduces the cost premium. Consumers could also develop greater acceptance for advanced higher-cost windows if more utility programs offered incentives and financing for these products. This is a possibility because utilities are more likely to offer incentives based on less-inclusive criteria that promote leading-edge performance.

While it remains to be seen what exact balance EPA will strike between inclusiveness and exclusiveness, there are other options for differentiating the best-performing cold-climate windows. For instance, EPA could decide to pursue a "Most Efficient" recognition for windows. The Most Efficient designation is currently reserved for the leading edge of Energy Star refrigerators, clothes washers, televisions and HVAC equipment but could be expanded to windows. Even in the absence of a Most Efficient designation for windows, leading-edge triple-pane windows can be marketed through the Washington-based U.S. Department of Energy's High Performance Windows Volume Purchase Program ( This program was started in 2010 to connect purchasers with vendors of highly efficient windows for new construction and replacement. While the emphasis has initially been on larger buyers such as weatherization agencies and home builders, the website also allows smaller customers to find advanced product options. Participating windows meet rigorous specifications, including a U-factor of no higher than 0.22 for exceptional insulating performance.

Aside from windows, the Energy Star revision also covers doors and skylights through separate criteria. EPA will address the combined revision proposals for windows, doors and skylights in its criteria and analysis report, scheduled to be released this month, and at the stakeholder meeting scheduled for April. For information on how to get involved in the Energy Star for Windows, Doors and Skylights revision process, go to


Nils Petermann is program manager at the Washington, D.C.-based Alliance to Save Energy for the Efficient Windows Collaborative, a joint project of the Alliance and the University of Minnesota in Minneapolis, with funding support from the U.S. Department of Energy, Washington.