The U.S. Environmental Protection Agency finalized the Version 7.0 Energy Star Specification for Residential Windows, Doors and Skylights on Oct. 20. The new criteria will go into effect on Oct. 23, 2023, with products meeting the new criteria eligible for early certification starting immediately.
This action is the result of a four-year collaboration between EPA, the U.S. Department of Energy and Lawrence Berkeley National Laboratories that involved modeling the energy characteristics of a range of high-performing windows in different operating conditions.
The Energy Star performance criteria for WDS are based on four different climate zones. Qualifying windows for the Northern zones must significantly lower the heat flow (U-factor) out of the house. Products made for the Southern zones must achieve a lower Solar Heat Gain Coefficient (SHGC).
In a note to Energy Star Residential Window, Door and Skylight partners and stakeholders dated Oct. 20, Doug Anderson, product manager for windows, doors and skylights, wrote, “The Energy Star Version 7.0 specification provides a significant jump in efficiency and savings and will recognize a good selection of types and styles of products offered by a variety of manufacturers at a range of price points. If all residential windows and doors sold in the United States were certified to Energy Star Version 7.0, the energy cost savings would grow to more than $156 billion each year and more than 53 billion pounds of greenhouse gas emissions would be avoided annually.”
New Data Analyzation
As part of the effort, several new ways of analyzing WDS data were developed. These improvements include:
- The development of a new methodology for analyzing the National Fenestration Rating Council’s Certified Product Directory, which contains thousands of products lines and millions of product options.
- An update to the energy modeling analysis performed by LBNL using the latest EnergyPlus software version and modeling, which was expanded to over 130 different locations across the U.S.
- Over 280 different U-factor and SHGC combinations were modeled for each location and the results were combined by climate zone.
The resulting analysis required over 600,000 modeling runs.
Comments and Changes
The specification revision process involved several rounds of EPA proposals and formal comments from more than 60 stakeholders, including product manufacturers, utilities and energy efficiency groups. See the proposals, comments and comment responses.
Anderson expanded on several comments in his letter:
“EPA received several stakeholder comments on the Final Draft which EPA had previously considered and replied to in full. EPA received a few additional comments that did not result in a change to the final criteria but are touched on below. One comment, however, did result in a change.
"Numerous stakeholders shared a common concern regarding the availability of efficient > ½-Lite doors. EPA reevaluated its data and confirmed low availability for this subcategory of doors. As such, EPA made a very modest adjustment to the North/North-Central zone U-factor requirement for > ½-Lite doors moving it from = 0.25 to = 0.26. This change will allow a greater selection of > ½-Lite doors to qualify.
“EPA received comments from several stakeholders suggesting that the window criteria for the North-Central zone be made less restrictive by raising the U-factor from = 0.25 to = 0.26. EPA considered this request but decided not to proceed as EPA’s analysis showed that a good selection of window products is currently available at the = 0.25 level, the majority (over 60 percent) with dual glazing.
"Other stakeholders asked for a delayed effective date of Jan. 1, 2024. Recognizing that leadership products already meet the Version 7.0 criteria and the scheduled effective date serves the intention of allowing partners to transition collateral material, EPA will maintain the Oct. 23, 2023, effective date. Lastly, a few stakeholders raised a spacer modeling issue and requested an easing of the criteria. While the issue is unfortunate, several alternative approaches exist in the market that can be used to achieve equivalent or better performance. Therefore, no adjustment is warranted.”
Timeline and Next Steps
EPA has established the following timeline:
- Effective immediately, manufacturers may elect to have their Certification Body (CB) certify their eligible products to the Version 7.0 requirements.
- On April 23, 2023, CBs will be instructed to stop certifying new product submittals to Version 6.0. Note, however, that existing certifications will remain valid for purposes of Energy Star certification until October 23, 2023.
- Any residential windows, doors, or skylights manufactured as of Oct. 23, 2023, must meet Version 7.0 requirements to be Energy Star certified and bear the Energy Star label.
Energy Star partnership as a manufacturer is limited to organizations that own and/or license a brand name under which they sell eligible products in the U.S. Partnership is not available to original equipment manufacturers that do not sell directly to consumers or end users. OEMs may certify products on behalf of the Energy Star brand owners/licensees; however, the brand owner must be the Energy Star partner associated directly with the certified product models because only partners are authorized to use the Energy Star certification mark.
Version 7.0 criteria revision will require that all partners update their product labels with a new map since the climate zones have changed. EPA has also updated the label layout, provided a bilingual Spanish-English label option, and updated the spine labels.