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Good Windows Are Getting Better!

DOE ZERH’s Changing Window Specifications

ENERGY STAR-labeled products distinguish the top products in the marketplace. As residential windows have advanced and the high performance windows of several years ago are now the standard product, the ENERGY STAR window program has raised the bar on its qualification criteria.  Because the DOE Zero Energy Ready Home program requires windows with ENERGY STAR specifications, our program is now phasing in the updated window requirements. Weve highlighted this change in communications and training since early 2015, but we wanted to offer this reminder because we are approaching a key date. For DOE Zero Energy Ready Home partners, here are the key takeaways:

In the Hot and Mixed zones, the updated ENERGY STAR window specifications required for DOE ZERH are shown below in the chart. Keep in mind that DOE Zero Energy Ready Home allows area-weighted averaging for U-Value and SHGC, as well as an exception for passive solar design exemption.  (See Footnote #13 in our program requirements.)

For projects in the Cold zone (IECC Climate Zones 58 & Marine 4), DOE ZERH has phased in the updated window specifications. For projects permitted after 8/31/2016, the new windows specifications shown in the chart will apply.  There are 2 important points about these updated specifications:

1 There are 4 different U-Values called out in the ENERGY STAR window specifications with corresponding SHGC values, as the chart shows. This provides flexibility for project specifications.

2 Area-weighting of U-Value and SHGC for the entire window package is permitted. (See Footnote #13 in the program requirements for details.) 

If you have any questions about the new window provisions, or any other program requirements, please contact us at

Source: Zero Energy Ready Home Newsletter at

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