Guidance for Windows

The ENERGY STAR 7.0 specification represents a significant update to EPA standards. ENERGY STAR-certified products will need to meet even more stringent U-factor and SHGC requirements than before.

Window and door manufacturers can now prepare their product lines to meet the new certification standards. This document provides general guidance to select the right insulating glass and LoĒ glass coatings to meet the new criteria.

What’s New

Effective date: October 23, 2023

Each of the four climate zones have updated boundaries

More stringent U-factor and SHGC requirements across all climate zones

New ENERGY STAR 7.0 Climate Zones





For a detailed list of county zone assignments, see the ENERGY STAR website.

ENERGY STAR 7.0 Requirements for Windows
Climate Zone U-Factor SHGC
Northern ≤ 0.22 ≥ 0.17
= 0.23 ≥ 0.35
= 0.24
= 0.25 ≥ 0.40
= 0.26
North-Central ≤ 0.25 ≤ 0.40
South-Central ≤ 0.28 ≤ 0.23
Southern ≤ 0.32 ≤ 0.23

For the Northern zone, a manufacturer can choose ‘equivalent energy performance’ criteria which should match the annual energy performance of the ‘prescriptive’ criteria. This offers more flexibility in window selection.

Cardinal’s Product Selection Tool

The following table describes the LoĒ coatings and IG configurations that could meet the new criteria. This information assumes that the IG unit is configured with an energy-efficient window frame and is properly installed. Connect the LoĒ coated glass on the left with the correct climate zone column. Examples here use 3mm glass with a stainless steel spacer and argon gas fill.

2 Pane

Only need a 2-pane IG unit with the specified LoĒ coating.

2p i89

Need a 2-pane IG with LoĒ coating and room-side LoĒ-i89.

3 Pane

Need a 3-pane IG unit with the specified LoĒ coating.

This configuration cannot be used for ENERGY STAR 7.0.

Northern North Central South Central Southern
Prescriptive Equivalent Energy Performance Prescriptive
U-Factor ≤ 0.22 = 0.23 = 0.24 = 0.25 = 0.26 ≤ 0.25 ≤ 0.28 ≤ 0.32
SHGC ≥ 0.17 ≥ 0.35 ≥ 30.3 ≥ 0.3 ≤ 0.40 ≤ 0.40 ≤ 0.23 ≤ 0.23
LoĒ³-366 3 Pane 2p i89 2 Pane 2 Pane
LoĒ³-340 2p i89 2 Pane 2 Pane
LoĒ²-240 2p i89 2p i89 2 Pane
LoĒ²-270 3 Pane 2p i89
LoĒ²-272 3 Pane 2p i89
LoĒ-180 3 Pane 3 Pane 3 Pane 2p i89 2p i89

We’re Here to Help

When using this data, keep in mind that the entire window assembly, including the frame, sash, decorative bars, and other hardware can influence the overall performance numbers.

This document will be updated periodically to reflect any adjustments to Cardinal’s product lines.

Additional questions from window and door manufacturers can be provided through Cardinal CG Technical Services or your sales representative.

Page Updated: 02/01/23