The U.S. Environmental Protection Agency has released the Energy Star Most Efficient 2020 final recognition criteria, which encompass 14 product categories including residential windows and sliding glass doors (SGD).

The Energy Star Most Efficient program provides businesses with the opportunity to be recognized for meeting a higher standard than the baseline Energy Star criteria.

Efficiency standards for the window and SGD segment are calculated using the Northern, North-Central, South-Central and South climate zones (CZ) and did not reflect any changes for the 2020 standard. The standard for U-factor in all CZ has remained at less than or equal to 0.2 and for Solar Heat Gain Coefficient (SHGC) standard in the South-Central and South CZ stayed at less than or equal to 0.25, in the North-Central CZ less than or equal to 0.40, and in the Northern CZ greater than or equal to 0.2. However, the final criteria for residential windows were updated from 2019 to now include specific SGDs as outlined in the criteria.

Overview of 2020 Standards:

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

The Energy Star certified products meeting the requirements will be highlighted as Most Efficient for 2020 on the Energy Star website starting January 1, 2020, and running through December 31, 2020.

The EPA released the final recognition criteria after a period of receiving stakeholder feedback on the previously proposed updates through various mediums including a webinar held on August 7, 2019, and written submissions received between July 22-August 22, 2019.

During this time a comment was submitted expressing concern over the effect proper installation practices can have on energy efficiency. Upon suggestions that the current Energy Star program requirements that manufacturers provide best-practices installation instructions are inadequate, EPA responded that specific recommendations were not provided therefore inhibiting them from further action at the moment.