EPA Finalizes Most Efficient Requirements

November 20, 2012

The U.S. Environmental Protection Agency sent out a letter today announcing final recognition criteria for the Energy Star Most Efficient 2013 program for 11 product categories, including windows.  Reflecting changes put forward in a second draft at the end of October, the final criteria include:

  • A U-factor ≤ 0.20 across all climate zones
  • SHGC ≥ 0.20 in the Northern Zone, SHGC ≤ 0.40 in the North-Central Zone and SHGC ≤ 0.25 in the South-Central and Southern Zones
  • North American Fenestration Standard/Specification (NAFS) Performance Grade ≥ 15

The EPA letter notes doors, skylights, tubular daylighting devices and dynamic window products are not eligible for recognition in 2013, but may be considered in the future.


For window products, partners will need to apply for recognition in order for EPA to verify that a product meets the recognition criteria outlined above. At a minimum, partners will need to submit the product’s National Fenestration Rating Council Certified Products Directory Number, evidence of NAFS certification, and test reports indicating a Performance Grade of 15 or better. Detailed application instructions will be provided shortly, it states.

Once EPA has confirmed product eligibility for recognition, the Energy Star Most Efficient 2013 designation will be provided, along with usage guidelines.  The letter points out that the Energy Star Most Efficient 2013 designation is intended for use at point-of-sale on point-of-purchase materials, product literature and websites. It may not be factory-applied to products or product packaging, with failure to abide by the guidelines  potentially resulting in loss of recognition.

EPA will highlight recognized products on the Energy Star Most Efficient 2013 web page through December 30, 2013.