ICC Reduces Residential Fenestration U-Factors During This Week's Code Hearings
October 30, 2009

The International Code Council's Code Development Hearings are currently underway in Baltimore. A number of code change proposals for the International Energy Conservation Code (IECC) were presented, resulting in several changes.

EC13, proposed by the Department of Energy (DOE) was approved, resulting in reduced U-factors for residential fenestration and skylights. Shortly thereafter, ICC passed EC34, which further reduced residential fenestration U-factors in the South. This resulted in the following U-factors: "NR" (no requirement) for zone 1, 0.40 in zone 2, 0.35 in zones 3-4 and 0.32 in zones 5-8.

According to Dr. Thomas D. Culp of Birch Point Consulting LLC, "The northern changes in U-factor were not very controversial, but there was strong debate about southern U-factors, with the concern that these U-factors would not allow aluminum windows in places like Florida and Texas where they are common. On top of this, [ICC] then eliminated the allowance for hurricane impact-resistant products with higher U-factors (approving EC35), over strong debate about safety, structure and performance of different products. These are just initial recommendations from the code development committee, and these items will no doubt be controversial items at the final action hearings, where final approval or changes are made by the code officials."

Regarding solar heat gain coefficients (SHGC), several proposals were debated, but in the end, no changes were made. The requirement remains SHGC < 0.30 in zones 1-3.

Items disapproved include:

  • EC41 - which would have reduced SHGC to 0.25 in zones 1-3;
  • EC42 - which would have reduced SHGC to 0.40 in zone 4;
  • EC43 and EC73 - which would have introduced a minimum SHGC in zones 5-8; and
  • EC29, EC36 and EC37 - which would have introduced separate SHGC requirements for skylights ranging from 0.35 to 0.40.

One other proposal from DOE, to limit the amount of west facing glass, EC78, also was disapproved.

Culp notes that these are preliminary hearings, and any item can change at the final action hearings in October 2010.

Stay tuned to USGNN.com™ for more code hearing updates as they are made available.

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