With the next version of the energy standard a year away, work on ASHRAE Standard 90.1-2016 has been ramped up—and the topic of U-factors has been in its crosshairs of late.

Earlier this month, code consultant Tom Culp of Birch Point Consulting gave a presentation at the Glass Association of North America’s Building Envelope Conference on code changes, and discussed future potential changes in the energy standard.

Culp said there has been a “heavy emphasis” over the last seven months on updating the window criteria for the 2016 version of 90.1, and much of that discussion has been in regard to U-factors for fenestration in zones 4-8. After hours of debate and close votes at the subcommittee level, the group was “very successful in achieving our goals,” said Culp.

A proposal, which was voted on for public review in January and went out for public comments this March, includes a 10- to 14-percent reduction in U-factor in zones 4-7—a “realistic and practical” compromise, as some proposed as much as a 20-percent reduction.

Culp broke down examples of how the proposed requirements would translate to products used, which are as follows:

Zones 4-5
Low‐E, thermally broken frame and pick 1:
-argon;
-high performance thermal break;
-two low‐E coatings (surface 2 and 4).

Zone 6
Low-E, thermally broken frame and pick 2:
-argon;
-warm edge spacer;
-high performance thermal break;
-two low‐E coatings (surface 2 and 4).

Zone 7
Low-E, thermally broken frame and pick 3:
-argon;
-warm edge spacer;
-high performance thermal break;
-two low-E coatings (surface 2 and 4).

Zone 8
-“All of the above in double glazing, or more likely, go to triple.”

Other items still under discussion, according to Culp, are possible small changes to U-factor in zones 2-3, “to ‘smooth’ the large jump in performance between zone 3 and 4.”

Comment deadline for the U-factor proposal is April 27, as listed in the March 13 edition of the ANSI Standards Action document.