DOE Issues New 2010 Energy Star Proposals

March 11, 2009

The Department of Energy issued its revised 2010 draft criteria for the Energy Star windows, doors and skylights program. In its full report, DOE officials state that changes were made from previous proposals based on industry feedback, the new tax credit requirements set forth in the stimulus package and the final window performance requirements established by the 2009 International Energy Conservation Code.

The full report on the revised Phase 1 criteria notes that DOE has elected not to issue its Phase 2 criteria at this time. DOE will delay work on Phase 2–a set of more stringent numbers originally proposed to go in effect three years after the first round of changes–until late in fiscal year 2009.

Fig. 1

Among the most notable changes made in the revised proposal is a reduction in the number of climate zones in the Energy Star map (Fig. 1). DOE previously proposed five climate zones, but elected to continue with four and keep the geographic names used in the present Energy Star guidelines. Industry stakeholders had argued that the additional zones and nomenclature would create too much confusion.

Other major changes concerned the window criteria (Table 1) for the Northern zone.  DOE tightened the U-factor criterion to the 0.30 level set by the ARRA tax credit to ensure that Energy Star intersects with the tax credit, officials noted. To maximize the number of products qualifying in the zone, DOE chose not to set an SHGC maximum. Previously proposed tradeoffs for the Northern zone were limited, as DOE determined it was worthwhile to recognize the benefits of higher solar gain some applications.

Revised Phase 1 Draft Energy Star Windows Criteria
 Existing Prescriptive Energy Star CriteriaFirst Phase 1 Draft ProposalsFinal 2009 IECCRevised 2010 Proposals
Proposed Climate Zone*U-FactorSHGCU-FactorSHGCU-FactorSHGCU-FactorSHGC
Table 1−*Draft climate zones are not the same as existing ones. NR=No rating 

In the Southern zone, the latest draft relaxes the SHGC to 0.27. DOE officials note that stakeholders had expressed concern that the very low SHGC previously proposed would have reduced visible light transmission, and DOE decided it did not want to encourage production of windows providing less visible light.

DOE also made the following changes in the new draft criteria:

  • Adjusted the U-factor for the ½-lite category of swinging entry doors and changed the SHGC to match 2009 IECC levels (see Table 2, below)
  • Changed skylight criteria based on industry comments and IECC levels (see Table 3, below)
  • Suspended tubular daylighting devices from the program until industry collects a sufficient body of test results.

The latest Energy Star proposals are scheduled to go in effect January 1, 2010, or at least 270 days from the date the final criteria are issued. DOE is accepting public comments on its latest draft revision until March 25, with a final draft to be released shortly thereafter.

Although it is not prepared to offer an official response to the new criteria, John Stoiber, president of the Window & Door Manufacturers Association, noted that the organization's members "found nothing shocking" in the latest draft criteria. WDMA is still working to gather feedback regarding the specifics of the proposed criteria, but he suggests that DOE had made "good progress" in addressing a number of industry concerns.  

Revised Phase 1 Draft Energy Star Criteria for Swinging Entry Doors

 First Phase 1 Draft ProposalsRevised 2010 Proposals
≤ ½-Lite≤0.25≤0.30≤0.27≤0.30
> ½-Lite≤0.32≤0.30≤0.32≤0.30
Table 2−NR=No rating 

Revised Phase 1 Draft Energy Star Criteria for Skylights
 First Phase 1 Draft ProposalsFinal 2009 IECCRevised 2010 Proposals
Climate ZoneU-FactorSHGCU-FactorSHGCU-FactorSHGC
Table 3−NR=No rating