EPA Issues Proposed Changes for Energy Star

October 14, 2011

Seeking industry comments and discussion, the Environnmental Protection Agency has released new criteria it is considering for the Energy Star windows, doors and skylights program. The proposals, which would take effect in fall 2013, include a maximum U-factor requirement as low as 0.25 for Northern climate zone windows.  

According to the Energy Star Windows, Doors, and Skylights Version 6.0 Specification Framework Document, potential additions to the progam include a maximum air leakage requirements and requirements for detailed installation instructions for qualified products. A number of possible changes to Energy Star that had been discussed previously, but which will not be addressed, include structural performance requirements and life cycle analysis for qualifying products.


Energy Star Window
Performance Criteria

Climate Zone
Current maximum U-factor
Proposed maximum U-factorCurrent maximum SHGCProposed maximum SHGC
North Central0.320.28-0.300.400.35-0.40
South Central0.350.30-0.320.300.25
Table 1   

Proposed Criteria
In discussing its proposed window performance requirements (Table 1) for the Northern climate zone, EPA says it "is looking to establish criteria that recognize the highest-performing doubles and bring a greater number of triple-pane windows into the mainstream." The document notes that due partly to the .30/.30 tax credit, windows with a U-factor of 0.30 are more readily available than in years past. At the same time, it is noted, "triple-pane products are still relatively uncommon and, based on our preliminary cost analysis, may not be cost effective."

Another proposed change for the Northern zone is the elimination of Equivalent Energy Performance criteria, which allowed products with a higher U-factor to qualify if they allowed more solar heat gain. EPA wants to get ride of the provision because few windows are engineered to take advantage of the trade-off and a minimal number of products qualified using these criteria.

Proposed revisions for the North Central and South Central climate zones are based on EPA's goal to have Energy Star U-value and SHGC maxima to be equal to or more stringent than code, it notes. For the North Central zone, the agency has determined, based on current product availability, that a reduction in U-factor is feasible, but that a significantly lower SHGC is not always ideal in this region.  For the South Central, EPA notes that the 2012 International Energy Conservation Code now meets the current Energy Star requirements for U-factor, and therefore, it will lower those requirements. The 2012 IECC ratcheted down the SHGC in the South Central zone to 0.25. EPA does not see value in lowering SHGC below that level and will match the codes.

For the Southern Climate Zone, again it is noted that IECC is lowering its U-factor requirements to 0.40. EPA is proposing the Energy Star criteria match that number, pointing out that it is a signicantly-lower number than the current level. EPA is considering a lower SHGC requirement for Energy Star than the new code, however. The 2012 IECC sets a maximum SHGC of 0.25, while EPA analysis suggests a U-factor of 0.22 is closer to ideal, officials note.


Energy Star Door
Performance Criteria

Glazing Level
Current maximum U-factor
Proposed maximum U-factorCurrent maximum SHGCProposed maximum SHGC
Opaque0.210.15-0.19No ratingNo rating
½ Lite0.270.22-0.250.30 0.25
> ½ Lite0.320.27-0.300.300.25
Table 2

Door and Skylight Performance   
The energy performance of doors varies significantly by the percentage of glazing, EPA notes, and the new critieria (Table 2) will once again be based on three glazing levels.  To maintain Energy Star as a clear differentiator in the market, EPA is lowering the U-factor and SHGC maximums across all three glazing levels. Based on its market analysis, the new U-factor requirements "should not be overly burdensome to manufacturers, nor should they be too costly for consumers."  

As for SHGC, EPA again notes that the criteria set in the 2012 edition of the IECC 2012 are more stringent than the current Energy Star requirements. EPA is proposing to lower the SHGC requirements for glazed doors to the lowest level set by SHGC to allow the Energy Star program to retain one set of door criteria for the entire country.  

According to the document, 99 percent of glass skylights meet current Energy Star criteria. "There is significant room to improve the specification while allowing many cost-effective choices for consumers," EPA states. Therefore, the agency is offering significantly more stringent U-factor and SHGC criteria proposals (Table 3).  Even with the changes, EPA notes "that efficient skylights with double glazing would be able to earn the Energy Star label."


Energy Star Skylight
Performance Criteria

Climate Zone
Current maximum U-factor
Proposed maximum U-factorCurrent maximum SHGCProposed maximum SHGC
North Central0.550.45-0.470.400.25-0.30
South Central0.570.48-0.500.300.25
Table 3   

New Additions
As noted, the next round of Energy Star criteria will include some new requirements, including an air leakage rating. EPA is proposing that windows, sliding doors, and skylights must have an air leakage rating of 0.3 cfm/ft² and swinging doors must have an air leakage rating of 0.5 cfm/ft². "Currently, a consumer could buy an Energy Star-qualified fenestration product and be unsatisfied with the tightness of the seal," the document notes. "EPA believes an air leakage requirement would help ensure that consumers are purchasing quality fenestration." 

Another reason EPA says it now adding the air leakage requirements is revisions in the National Fenestration Rating Council's testing specification that allow for the use of commonly-used tests, an issue that had previously prevented the Energy Star criteria from including air leakage.  EPA notes it will work closely with NFRC and stakeholders to determine the best way to label for and document compliance with the new air leakage requirements, with a number of approaches under consideration.

In highlighting its intent to add requirements for installation instructions to be provided with Energy Star-qualified products, EPA notes that "poor installation is the most common cause of poor product performance for windows, doors and skylights" and that poor installation is also "the primary source of nearly all consumer complaints received by EPA’s Energy Star program."  Therefore, EPA is proposing a requirement that manufacturers "make detailed installation instructions available to consumers and installers online." 

According to the EPA document, several options to meet this requirement are anticipated:

  • Manufacturers may develop installation instructions in-house and provide them on consumer-facing web pages.
  • Resellers, subsidiaries, private labelers, members of alliances, etc., would have the option of linking to installation instructions posted on the website of a parent company, original manufacturer, etc.
  • Trade associations can develop installation instructions and provide them on consumer-facing web pages. Members of those organizations can then direct consumers to the trade organizations’ websites.
  • Manufacturers without company websites would have to develop marketing materials that include links to installation instructions as outlined above.

The EPA document notes that several other program elements were considered for adoption, but that there is still insufficient data and/or little justification for at this time.  Most significant of these potential program changes was a requirement that products must be tested and certified to the North American Fenestrations Standard (NAFS) for structural performance.

Less than a quarter of Energy Star's partnership base currently participates in the American Architectural Manufacturers Association or Window and Door Manufacturers Association's certification programs, EPA reports.  "This raises concerns that requiring NAFS certification at this time may result in a backlog at labs and inundation of AAMA and WDMA resources. Thus, EPA proposes that the Agency reconsider this suggestion during the next criteria revision."

The new document also indicates that EPA has reviewed suggestions for special Energy Star criteria for products to be installed at high-altitude and for impact-resistant products for coastal applications. In both cases, EPA states that a sufficient number of manufacturers have found ways to address the specific challenges of such applications and still meet the regular criteria.  As a result, it has determined that no separate set of criteria are required in these cases.  

The latest document "is intended to facilitate discussion of this assessment and possible resulting modifications," with EPA asking for comments from stakeholders by November 18. The tentative timeline for the next set of revisions include a draft release in March 2012, followed by a stakeholder meeting in April 2012.  After an additional comment period, the new Energy Star program requirements would be announced in fall 2012 and take effect in fall 2013.